Poor service

Received a sms that my data contract will expire, went to the mtn shop and was told that the contract has expired in December 2019, because i was given only half my data the one month by mtn mistake and after many phone calls the problem was not rectified and i was left without data for half a month i promised mtn that i would cancel my contract when it is due, it is now due and i have been trying since last month to get the contract cancelled, because of this i will be cancelling all 3 my contracts as they become due, this is poor service and i know i'm dust a drop in the bucket and they don't care so i will take my business where i get quality service, i want my contract cancelled.