Synovus Bank Credit Card Complaint

Synovus Bank Credit card department,

Billing disputes California

I have a secured credit card through First Progress. I deposited $400.00 with them so I have a credit limit of $400.00 with a balance of $340.00. That means I had available balance of $55.00. I sent - check on -/-/16 in the amount of $50.00 then proceed to send a - check in the amount of $400.00 on -/-/16 to over pay my credit card. First Progress received the money for the - check and took the money out of my account and posted it. That means I should have a negative balance of about - $100.00. They then proceed to tell me that I have an available balance of $0.00. They told me I have to wait 10 days to use my card again because I over paid it. My money is being held hostage and they take my money but will not allow me to use it. They are holding my funds while being in good standing and paying my credit balance before the due date while always paying more than the minimum every month.