Rcs credit card

Last year I paid all my accounts including my game credit card. Just a month after that I started to recieve statements again saying that the account is in arrears. For months now I sent emails and last week for the first time after I asked again what was the other account I paid with the amount that was owed, thry said that it was the old credit card number that I paid, but the 2 is the same account. They deducted thousands after I paid the account as the 2 account numbers differed. Now I have sent a few emails asking to give my money back that they deducted after I settled the account, and getting no response. They need to give the money back as I have paid the account more than six months ago, and they deducted money each month after that. I dont know ehat do do anymore. Every time I phone, they give me thr email address, and I send them emails over and over. Will I ever get the monthly settlements back that they deducted? Cause that account, even as its closed now, should be a few thousand in credit. But they just dont reply . I even sent bank statements to show them the deductions, no reply.