How could my chess opponent who was losing just disappear?

I was playing an American person but after I got the upper hand he just disappeared. What is strange in my opinion is that there is no trace after him, not even such that I played him, so while winning I did lose my points of upgrade by that disappearance act.

I ask, how is this possible on a "seemingly" serious chess playing site? I have not got so sceptical that I consider leaving chess.com, for I do not accept that such things are allowed to happen!

Is there a reasonable answer to what I experienced. I get angry at thinking about it!

Greeting, Albbas