Why do the employees argue with the customer (listen to recordings)

I received my new credit card last month & so my Vodacom debit order did not go off.I tried to phone Vodacom on 20 October to resolve – WHAT an inconvenience I was subjected to - ie call centre can’t change expiry date, customer cannot phone accounts dept. they will phone when it is convenient for them not the customer. Consultant asked me whether I wanted the debit order to go off 26 October or 1 November. I said they could choose as long as I was not inconvenienced ie not cut off and could do a sim swop – consultant said double amount would go off 1 November and I thought all was sorted. Went to Vodacom shop on 23 Oct to do sim swop as desperate to use new phone with old no but told account locked cos of my arrears. Phoned Call centre on 24 Oct– spoke to consultant who did not speak into the phone and sounded half asleep. She asked me 3 questions which I got right and another one re my package which I got wrong& then continued to as me more questions. I was irritated and asked why I was being asked so many questions – she proceeded to argue with me. I told her the story regarding my arrears and then she told me I was in arrears. Fed up & getting nowhere I asked to speak to the supervisor. I told him my story and he proceeded to argue with me too regarding the debit order - not understanding what I was conveying. He told me that the accounts dept would phone me which they never did. I eventually phoned the accounts department and got another inefficient consultant who I tried to tell my story to as well as express my frustration with the whole process only for him to misunderstand and argue with me too. He told me the debit order was changed to now go off the today 26 Oct. He was eventually getting rather upperty with me so I thanked him for his useless service and rated him very poorly. Needless to say the debit order has not gone off & I am unable to unlock my account to do a basic sim swop so I can use the service I pay for. The inconvenience & waste of time trying to resolve this issue is UNACCEPTABLE. Vodacom get people who understand what the customer is saying & who don’t argue. Never encountered so many argumentative employees at a call centre!