Once again MTN accounts department

i went into the MTN store on 27.09.2017, asked the consultant to check my account which was due the consultant gave me an amount of R 835.00 which i paid R 900.00. on Monday 2 October i receive an SMS saying i am overdue on R 101.94. i queried it with MTN who gave me a reference number saying it would be resolved and credited on my account. got an SMS on 10 October 2017 to say my query has been resolved with another reference number. 1 day later i get an sms stating i am still overdue R 101.94. i phoned MTN again today 11 October spent 20 min on the phone still my credit has not been done. had to log another "ticket" i mean really MTN get your accounts right pls and this is not the first time this has happend. i am really thinking of cancelling my contract and going to another network. i have been with mtn 8 years and never missed a payment. but yet the problem lies with u and giving a person a bad credit record.