Xfinity is charging me for a contract I canceled three months ago

Xfinity  is charging me for a contract I canceled three months ago

At that point, they calculated that the amount was $250. On July 18 or 16, I messaged them on chat to say I was withdrawing, and they replied that someone would call me. Someone did call, and I told that person that I was canceling; I also have a transcript of the chat conversation. Now they send me emails every day that I can’t reply to, and they call me, but when I answer, they hang up. This is crazy. However, I have written proof that my contract has been terminated; I’m waiting for the court case and substantial damages for the harassment I’ve endured.