I've tried my best on several websites/apps to find out what was that piano piece, but couldn't find anything. Any ideas?
I have added the piano piece on youtube
I don't think it's any established piece (and almost certainly not Beethoven, or anything from the classical period for that matter - the figuration and the syncopated rhythm against 3/4 bass sound quite modern to me). The music is straightforward enough that you can hire a musician to transcribe it for you, if you really want the piece.