Shocking treatment after 21 years.

I have a contract with MTN for about 21 years (Twenty One). There are 3 accounts on the contract, of which one was upgraded two weeks ago. I have a data contract at another provider which has now expired and I realised that the data on that contract has subsequently been reduce, leaving me with insufficient data. I decided to take out a data contract with MTN, as they have been me main service provider. I was at the MTN store twice yesterday, but they couldn't assist me, as they were off line. I went back today. My application was submitted and I received a sms informing my of such. Twenty minutes later, I received another sms with the same message. The lady at the store eventually called their call centre to find out why there was a delay. She was informed that I needed to submit an Account Confirmation Letter. I fail to understand the request, as MTN has been debiting the same account for the past 12 years and I didn't request any changes to my debit order details. At a cost, I was able to obtain the letter and I e-mailed it to the store. It was forwarded from the store to their credit department at about 2pm. I went back to MTN expecting my request for a data contract of R200.00 to have been approved. After waiting for a while, I was informed that the person at their call centre is unable to trace my current contract????? I went to the provider with whom I have the current data contract and bought additional data for R95.00 for 1GB of data. I can continue with the current data contract, but it is going to cost more than the MTN contract. After I buying additional data, I went back to MTN and was informed that they are trying to resolve the matter. It has cost me in excess of R200.00 to try and add another account of only R200.00 per month to my current MTN contract, thus it has cost me more to obtain a new account that what the monthly fee is for the contract. None of my debit orders over the past 21 years have ever been returned unpaid or stopped. It is totally embarrassing to be treated in this manner. I am considering to move all my MTN contracts to another provider, which in not what I really want to do, but after 21 years, I would have expected more from MTN. What I also can't understand is, why didn't a senior staff member intervened to assist in resolving this matter?