Very bad service

I have been with Vodacom for many years, and I have multiple cell phone contracts with them. I have been receiving my salary late for the past three months. Each time my debit order fails when I receive my salary, I always call Vodacom and make arrangements for them my premium. Last month I called them and I asked them to move my debit order date to the 8th of every month. Two days I received an sms telling my services has been suspended. I called their billing department, spoke to a lovely lady by the name of Noma, who assisted me and explained that she confused was confused because I moved my debit order date to the 8th and she activated my services, and she also explained that she will escalate the issue to her manager to make sure the issue does not reoccur again. Noma also reassured me that the debit that will be debited on the 8th May will only be R2036,44. and the bill for R1935.66 will be debited the in June. This morning when I woke up, my services were suspended again. I called again and spoke to an agent by the name of Busisiwe, who was not helpful. She informed me that because I moved my debit order date, on the 8th, Vodacom will debit a total of R3972. I explained to her that I have that balance in my account and when I called last month to move my debit order date, no one explained to me that I have to pay two premiums. I requested to speak to a manager, Busisiwe kept me on hold until my airtime run without out.