Bad service for a loyal customer

I have 3 contracts with cell c and have been a client of cell c for the past 10years. In the month of march i was contacted by the upgrades/sales department regarding 2 of my contracts that was expiring in April and May month. I briefly instructed the agent to upgrade 1 account (tablet) and cancel the other when it expires. On the 27th May i was debited an amount which i was not fami**** with. I contacted Cell C customer care on the 29th and queried it. They said i will be called back before COB on the day as they will pull and listen to the calls. I called again on 31 May and was told the same thing by a different agent who promised to call back before COB but did not. Today is the 1st and i followed up again and got the same response from the supervisor who still didn't call me back as she promised to call me before 12. I have been more than patient and can't wait any longer. Cell C, you have lost a loyal customer!!!