I have never had problems with this exchange, support always answers quickly. I do not know why you have such a problem. I think you should wait, I read that some people with such problems waited months.
The threads were full of complaints because of a poor support on Poloniex. Since they changed ownership this year, the support seemed to be much better.
Anyways, when one has no problem with Poloniex, that doesn't necessarily mean, that there are no problems on poloniex.
Back to OP.
When you are sure, that you didn't follow a link to a pishing site, there may be a problem with the sending address (the cloud miner, which sent your funds or a service, that isn't legal in the eyes of Poloniex, f.e. a crypto casino). But there is no reason to freeze whole account.
Maybe follow exactly the instructions by poloniex, if you didn't already:
https://poloniex.freshdesk.com/support/solutions/articles/1000166425-how-do-i-open-a-support-ticket-what-information-should-i-include-If nothing helps to get your account unfrozen and get an answer to your support tickets, try to reach them on their social channels and open a thread on scam accusations.
https://bitcointalk.org/index.php?board=83.0