Please allocate my cash payment from the month of May 2017 till to date

Hi am Reaitumela I am an mtn contract customers, on the month of May 2017 I've used a wrong reference number to pay my account and since then my account has always had an outstanding balance and now is September 2017 (I started to complain from the month of May 2017 till August 2017 but my problem is not resolved. I will highly appreciate it if my Incident can be taken into consideration.