disgusted with the service

in june i upgraded my phone, updated a new account number for a debit order and changed a date. they only updated the account number at a campus square branch, it bounced in july i went back to them and they told me there is nothing they can do let me rather pay cash, which did not make sense, the following month same story happened they debited on the 15th instead of the 20th, September it was still the sanme story and i decided to put a stop payment as i was the one being charged 115 for a failed debit order, on the 19th of october mtn blocked my number saying i owe as my debit orders were unsuccessful, i have been charged even though i have been calling them to change the datethey tell me it has been updated only for it to bounce again