Issues with Account Billing and Access Despite Charged Payment and Available Credits

I am having issues with my account billing and haven't been able to access it in 2 weeks. I was charged on 3/11. My account shows ~10,000/5,000 credits available, but still asking me to make a payment. I'm not sure how to fix this. I did not receive an email receipt for the charge and it says the last charge was on the same date back in November. This doesn't make any sense. 1) If you get charged your account should be unlocked and 2) If you have credits in your account, why wouldn't you be able to use them until they are gone. Right?