Disappointment

I pay my MTN account via EFT payments and usually pay a week before due date. Last Saturday I woke up to no service on my phone. Went in to my nearest MTN dealer and they just said they have unblocked the phone and my network will be back within 30 min. An hour later I had to go back since nothing happened yet. They said my bill was outstanding and that EFT payments take longer. I paid before the due date so this did not make sense. My account also amounted to +R1900 when it is usually R1042 a month and could not explain this to me. Then I paid again in the store and still nothing. After two hours it came out that my account was placed on a new system and that I had a new account number without my knowledge. My EFT payment reference was my old account number I have been using for years. They could not assist me with reactivating my service that day and I had to wait until Monday. How do you change an account number without notifying your clients and why was my bill R900 more expensive. The consultant that were helping me tried her very best and I appreciate her efforts but all and all MTN has really disappointed me.