I have the same problem. The stars stay at 15/15 and I do not get the 1000 stardust. No matter how many more levels I complete, I do not get the stars for it. Screenshot is attached.
Thank you both for attaching the screenshots. We passed the info to the Studio and they are investigating this issue. In the meantime, could you please both tell me which platform are you using? Also, @Claudia1306 could you provide me with your ID for the game?