Rewards not working

I am unable to play any instant win games or redeem gift cards. One customer service agent told me to clear my cookies and cache. The next agent said my account is flagged, but couldn't tell me why. It's frustrating not being able to use a service that I paid for with no reasoning and am wondering if I would be better off disputing the charge for my membership with my credit card. I would rather just be able to use my membership.