I've been doing e-rewards for over a decade, and in the last 1-2 years I've had my account frozen more times than in all the prior years, even though I have done absolutely nothing different or in violation of the T&C, and always provide them with honest answers. I think they may have stepped up their screening process to "catch" people who they believe are answering too quickly, and/or perhaps trying to answer too many surveys in a single day. (Total conjecture on my part.)

Typically what happens is that even though I can access my account, I have no surveys in the dashboard, and I stop receiving offers via email. In addition, when I try to redeem for an award, I get the dreaded "Error message QSB0303-17." In general, my experience after writing them has been that after waiting 7-10 days I receive an email with some boilerplate advice to clear the cache, try a different browser, etc etc. I write them back, politely tell them none of those things work, and there is something happening on their end. The next response usually comes several days later telling me that the problem has been resolved.