Unable to use GPT-4 after Payment

I just paid for GPT-4. When I ask it a question, it always leads me to solve a puzzle. After solving, it always displays the following error “Our systems have detected unusual activity from your system. Please try again later.”

I just paid my subscription.All I get is a puzzle then unusual activity try later. How can they do this? Take our money and provide no service worst still yiu cannot contact them. Is this some kind of scam because I am sure they do not give the lost day back.