Lack of communication and slobby work

Very disappointed with the lack of urgency when it comes to allocating funds. Paid my instalment on the 29th of June already and everytime I must get calls,SMS,and emails that the account is in arrears just hear when I called again today that I need to give them the banking details I have paid it into, so why did I send proof of payment thrice? For fun? I need you to sort this out ASAP because now I will be held accountable for arrears plus it's going to affect my credit score because of the lack of communication! After numerous calls being placed only find out now I need to give the account number totally unacceptable! Then still have the nerve to tell me I need to pay that amount that's in arrears no way!!!!