Barclays PLC Credit Card Complaint

Barclays PLC Credit card department,

Billing disputes Massachusetts

Last month I paid my credit card in full but when I scheduled the bank withdrawal by mistake I scheduled two payments for the same amount. The amount paid was the full balance for that month. When I realized that I paid twice, I called the credit card to let them know that I mistakenly paid twice. They said that they will credit back one of the payments, they did. The problem that I have is that the payment that was not retuned to my bank account has not been credited back to the credit card either. I called to ask why this payment was not credit yet. The explanation they gave me was that the money was returned to my account so they have to charge me again, which I do n't understand why. As today it appears that I still own the credit card what I already paid. I do n't understand their statement because it does not reflect that I actually paid. What are my options? I do n't understand how they are making my payment disappear? I like to mention that I pay all my charges at the end of each billing cycle to avoid this kind of problems.