Time trouble cheater!

I really prefer playing online cuz i avoid uncomfortable situations like this , time ago in some tournament there was a guy with just few seconds left so when i make my move he do the same with out letting me press the clock that was really annoying but i really didn't know what to do in that moment what can i do if that situation repeat ?

You stop the clock (lever arm in neutral position) and call an arbiter. This is consistent with both FIDE and USCF rules. Most decent chess clocks store a history that includes remaining time and move number throughout the game, and the arbiter should be able to deduce this.

Depending on the time control, the arbiter will add other one minute or two minutes to your remaining time. It is a violation of the rules to adjust or even touch the pieces on your opponent's time.

thanks @phoenixshade

Very few clock are stopped by lever on neutral position. Only the really old analog ones. there in the middle pause button pausing the clock use that and call arbiter. if opponent denies have done so he will not most likely get punished but arbiter will hang near by at least for a while.