Penalised for paying my account early

So I paid my credit card account earlier than usual (4days) in December as I wanted to avoid the public holidays etc and I didn't use the money for a week and it was just laying there, surprise I am being penalised for it. I called in to be told that the account is in arrears etc and its because I paid early. Because the account that they tried to deduct the money from was empty I was penalised with a fee which is understandable. So they eventually reversed the penalty fee on my account. Now I received an sms and e-mail to say regrettably you didn't pay your account so now your installment is almost double.