"You have bought this already!"
Translation:Już to kupiliście!
Unfortunately the course lacks the formal versions in a very big number of sentences. They were not provided at the beginning, and to add them everywhere now would be very hard and time-consuming. Of course we add them when requested. So added.
This one appeared in the "Formal you" section, that's why I was surprised it didn't work.
Oh. That's bad. But it's actually a sentence from "Verbs: Past Perfect", so this is one of the times when the algorithm randomly shows you some old sentence.