Lost a 500+ day streak despite paying for the streak freeze button with 10 lingots.
Since November, I have not gotten any lingots for 10 day achievements but continued out of a love for the lessons. I had over 850 lingots saved and, since I wasn't earning more, I began to spend a few by taking days off and paying to use the streak freeze button--religiously. Yesterday evening, I pressed the streak freeze button and chose not to do a lesson. This morning, my streak was reduced to one day. I am absolutely sure I did this correctly--as I have done many times before.
What's funny is that my incentive to stay has been reduced substantially. I've learned about as much as I can without beginning to spend more time conversing with other students or native speakers and, while I've known that for a while, I still enjoyed the lessons. My leaving won't change the world and I'm sure Duolingo will not investigate, but earning the lingots was nice--especially in 45 lingot increments--which is where I was when Duolingo failed--and I'm moving one.
What's odd is that I lost a 100+ day streak when I first started, too. This month marks my two year anniversary. Going to actually start paying for lessons now.
C'est la vie. Adios.
I have experienced the same dhitto thing as you did recently - I lost a 565 + day streak even with the Streak Freeze. Although I had already finished the course, it was the streak that kept me coming back. Then I built a 70+ day streak, which, due to another glitch, I lost just 2 days ago. After that, I don't feel like revising the lessons, but I will still be watching the Forums, doing Stories, etc.
By the way, I did make a post about losing my first streak, and sent an e-mail too, to which I did not get a reply. I will do the same for my 2nd streak - but only for the sake of others like you and me who I don't want experiencing the same problem.
We must also understand that these glitches keep happening and Duo tries it's best to remove them. And don't leave Duo - there is more to it than the lessons!
I think this is a sign that you should take the next step towards learning the language. Find a penpal, start reading, or start watching movies/tv. Practice some longform composition. Visit the country.
Just remember that the purpose of the endeavor is to learn the language, not to earn a high score on a random internet program. You are right in noting that as duolingo currently exists, there is only so far it can take you. Now that the program has taken you as far as it realistically can, it's time to dial back your time investment in this program, and redirect that time to other methods that are going to help you go further. Paying for lessons is an excellent step in the right direction. Some other approaches that will help you, which you may want to consider as a supplement:
1) Reading. Pick a book (for me in German, French, and Spanish that was Harry Potter because it was a fairly easy reading level and I was familiar with it). Set aside 30 minutes to an hour every day and read it. Every time you come across a word you don't know, or a passage you're unsure about, highlight it. Look up every word, and make it into a flashcard. Be honest with yourself. The purpose is to learn new words and see grammar in action, not to get through the book. If you're even the slightest bit unsure of meaning, stop and look it up. When the timer runs out, finish at the most convenient spot, and close the book. Study those flashcards every day. The next day, before you set your timer, run through the passage you read the previous day, and review the highlighted sections. It's important not only that you memorize the words, but that you remind yourself of how those words are used in context. This has a synergistic effect: seeing the word in context reinforces it's meaning and also makes the flashcard easier to remember.
2) Listening. Choose a time a certain number of times a week. Think of it like the gym. On Monday, Wednesday, and Friday, for instance. On each of those days, spend 30 minutes to an hour listening to a podcast or radio program, or watching a movie or television program in your target language. Watch with a notebook. Any time you hear a word you don't know, write down that word. At the end of the time allotment, run through your notebook, look up each word in turn, and make them into flashcards. If the word already exists (because you encountered it in reading), see if you can't find its use in the book where you first encountered it. Again this works synergistically as each time you encounter the word in a new context its meaning and use is reinforced.
3) Writing. Buy a notebook. Devote ten minutes each day to writing in that notebook in your target language. Write about whatever you feel like. No dictionaries. The purpose is to generate language on command for ten minutes without distraction. Looking things up in a dictionary breaks that flow, and forces you to return (however briefly) to thinking in English. If there's something you want to say but can't, then don't write it in the journal. If you remember it after the 10 minutes are up, then you can look it up. Convert that phrase or word to a flashcard. Again, if the word is already in your flashcard set, then try to figure out where it came from (this is the benefit of using a flashcard app like anki where you can tag the card with its place of origin) and review its use there. Periodically review your journal entries. Seeing visual proof of your improvement is a great motivational tool, and seeing evidence of stagnation is a great way to remind yourself which things you need to focus on.
4) Speaking. Find a penpal. There are plenty of websites that can help you connect with native speakers. Try to speak with them at least once a week over skype or coffee or whatever. When speaking, don't ever switch out of the target language. For any reason. If you have something you need to say, speak paraphrastically (e.g. if you've forgotten the word for "pool", don't say "un pool" or "cómo se dice pool", rather say "Yo me olvidé la palabra, pero el lugar con agua dónde se puede nadar" or something like that. The point, again, is to force yourself to think of the language in relation to itself, rather than in relation to English.