You are a communist

"No you are a communist"

"Well I'm a registered voter in a Democratic Republic who votes regularly...Did you vote?"

This claim is completely inane and scorn is probably deserved. You do not need to argue with such a claim as it is merely a fallacy (ad hominem and straw-man). You can argue past it to an audience and then say "next" or pass by the claimant without any acknowledgment.

For further information on a similar fallacy, see..

Reductio ad Hitlerum