Bad service in general

One of their stores call you up and tell you that your contract is up for an upgrade. You go in and process your upgrade, they do not tell you that you going to get billed an extra amount which they call pro-rata on top of what your contract says. So my contract says R599 on the upgrade and then I go download my December invoice and suddenly I see they going to debit my account over r1000. 00 for December because of this pro-rata and extra bill for doing the upgrade. You log a query with them and all they tell you on a sms is your query has been resolved! You get no feedback from them at all. This is absolutely disgusting and I have been with mtn for over 10 years now