Vodacom - Poor service

I have had several contracts with Vodacom over the past years, and have always been a good paying customer. Over the last few months I have had several phone calls from Vodacom asking whether I would like to upgrade or make changes to the contracts. Once they phoned and asked whether I wanted to do an upgrade on one of the phones....I told them not to upgrade, when I went into a store they told me that an upgrade has been done on the number and that they can't fix the problem they will log a complaint.....up until todat nobody has phoned me. It has been 3 months now. Then they phoned to offer me a better Data contract than the one that I had for less... they said that it would be R149 for 10GB instead of the R199 for 5GB. When I went into a store they never made the change and the offer was not available anymore. Then for sometime I was unemployed and couldn't pay January's installment....I phoned them and made an arrangement to pay half of the outstanding amount at the end of Feb 2018 and the other half end of March 2018. Yesterday when I got my account they had deducted the full outstanding amount at once. I am so disappointed in the poor service, and when you go into a Vodacom shop they can never help you there, you always have to phone a number?????