You can report through the Support tab to your left. You will have to enter the sentence from the top of this discussion and their translation and the alternate translation that you feel should be added. You did not show us what you entered, so it is hard to know if it was denied for some other reason. Both they and you should be accepted, but sometimes there is a typo or something. I used to press the enter twice to go quickly along, and I would occasionally miss why my answer was not accepted. I only press enter once now, so I can thoroughly look for the slip we all make at times. Also, you can press the Home tab on top and redo the German lesson in the German tree this was in (Was this in the 2nd lesson for accusative pronouns? Otherwise, it would have been in the 1st lesson for accusative pronouns.) A little practice is always good to refresh the memory. I would wait a while to see if Support made the change,
There are three different words for "you" in German: du (you familiar singular), ihr (you familiar plural; y'all) and Sie (you formal). "You pay/are paying" can be translated as "du bezahlst", "ihr bezahlt" or as "Sie bezahlen".
"Sie" is the "formal you". It's used to address one person or several people formally, e.g. one or more adult stranger(s). The verb for "Sie" (= you formal) takes exactly the same endings as the third person plural "sie" (=they). You can distinguish between "you formal" and "they" only from the context and from the fact that "Sie" (= you formal) is always capitalised, even in the middle of a sentence. By contrast, "sie" (= they) is only capitalised if it's the first word in a sentence.