Danny Rensch is the founder and owner of the website
This is a video in which he explains the accuracy number and what it actually means. (CAPS score).
Also, I won't get into the cheating thing for obvious reasons it isn't really good to discuss methods, but I'll just say that it's unfortunately very easy to cheat but luckily chess.com has a very good system for detecting it.
You're fine, I actually think it's quite funny when someone accuses you of cheating because it's like they are complimenting your play. They can whine about it in a forum but at the end of the day Chess.com will make the right call.
Stockfish, the computer I use, is the best chess engine so far (with the exception of a few computers that may have escaped my memory). I believe that it calculates the score correctly. Who is Mr. Rensch? and what is CAPS?
By this I mean no disrespect, but what can they do? Hook a computer to their account? Then they'll make the best move every 0.1 seconds, and that would be obvious. I suppose they could have another search engine alongside the game, but even then, it would take at least a second to process the move your opponent made, another 2-3 to plug it into the computer, and then 5-10 for the computer to calculate. It is irrideal for blitz games.
I apologize, I meant to say "Post an entire forum on the matter", and I just advised him to not make such a big deal about the event.