Account Closed and still getting billed!!

Good Day, <br> <br> In March 2015 my father paid up his account and then asked what the procedure was when closing your account and cancelling your policy as he would like to do that now, Cashier said \Just don't buy anything sir". April came and he was all of a sudden billed for \"" Sms air subscription & mobile content fee\"" which never reflected on any of his previous bills. He went to the branch and he asked them to check whether his account was closed because he was still getting billed and they said yes sir it is. May came and another bill and again he was billed for \""mobile content fee\"" by now his furious and went back to the store showing them his still getting billed. The called head office and the person assured my dad that it shows that his account has been closed. June comes and he received a letter stating that his been given over to the credit bureau because no payment has been made. Today low and behold ANOTHER bill comes! This is beyond RIDICULOUS and UNPROFESSIONAL!!! I urge you to correct this problem Immediately! Ensure that you clear my dads name with the credit bureau"