Endless Billing Problems with MTN

A few months ago I changed my Debit order details for my S3 contract with MTN at Coastlands, Umhlanga. The consultant took my details and said everything is in order but no debit orders went through since. I only get arrear sms's and MTN cutting my line (Even if I pay it in time before the required dates) , which is very frustrating as I need my phone to be active at all times. My latest issue started in June, as usual, getting arrear sms's, I paid this immediately (attached proof of payment), informed collections I have paid and pleaded with them not to cut the line. These guys kept sending me outstanding amount sms's (Although paid). I continuously reminded them that this amount is paid, I was even promised that it would be lifted but still no action had been taken. I spoke to Reuben from MTN Coastlands, asking for his help, he said he cannot upgrade my contract and I must come back another day because they cant get hold of the head office. When I went back there, he called MTN but still he was unable to help me. Offering me no solution, only an apology. It is clear that MTN does not require my business and do not focus on good customer experience.