Vodacom continues to fail on my requests

Story 1: On 30 Jun 2017, I phoned ********** to cancel my insurance. When I received my statement in Aug I was still being charged. I phoned them again on 11 Aug, they confirmed that the insurance was cancelled and promised that the I will be refunded with the R322.00 in my next invoice. Got the invoice today, they refunded me with R112.31 and charged me R74.56 for insurance again! Story 2: On 29 Aug I phoned to change my address. I was promised that the details were changed. The invoice I received today still has the old address! This is the second time I write a review on Vodacom. I don't even want to phone the call centre because I can guarantee you the IVR is going to say "we are experiencing high call volumes" and I can also almost guarantee you that the agent is going to tell me that their systems are slow. Vodacom, please sort out my stuff first time around. Why must I continue to do follow up calls!