Is this correct that "sweets" should be translated by "doce" and not "doces"?
Yep. Both are correct, no matter singular or plural. So your sentrence makes sense. Just report it!
What's the best way to report something if I'm no longer on that page?
I think you should press the link support back down your home page!
Thanks! Actually, I pulled down the list next to the tools icon (a gear), then "help", and "contact us" down at the bottom of the page.