I have done something similar to your opponent.  My opponent took my queen very early on and it set me back on my heels.  I could immediately have resigned but decided not to do so until I'd looked at the position to see whether my opponent and I might still get some pleasure from playing out some more moves.  I did not give a high priority to this but a day or two later I had spent a few minutes looking at the position and decided I would play on. I had read a couple of articles about the queen for two rooks exchange and wanted to see how dominant my opponent's queen would be. I did not have a plan and another day went by until I bothered to find another couple of minutes to settle on some way to go about further play.  It was a three day time limit and I think I had four or five hours left by then.  I subsequently played out the game with my usual rhythm.

Which means I am not so sure as you that your opponent was motivated by spite.

My opponent held no grudge because we subsequently played a couple more times together.

Just set the time controls to what you can live with and enjoy the game and ceaase the....

this is true.  or waffles.  waffles are always considerate.

no

Chess.com should create new time controls for exactly this kind of problem.

Instead of a simple time control of 14 days, for example, they should have composite time controls like 14/7/3 days: you get up to 14 days per move when you're being considerate, up to 7 days when you're being neither considerate nor inconsiderate, and only 3 days when you're being inconsiderate.

Once again people try to change time controls retroactively after a game has begun.

There is nothing wrong with using your allotted time. In fact, intelligent players who have been around the game a while understand that if you don't use your reflection time wisely you lose the game on the board, or lose the game on time.

That's chess.

Whiners go elsewhere.

Other solution :join a few new games and forget about this guy,when he make the move,then  you take 14 days to move and so on and You dont care no more ,continue enjoy chess with other nice people until He get tired and resing.

lol, i totally agree with you.