Incorrect bill and credit

I have had 2 contracts with mtn for 2 years last year 31st November I had upgraded the two out of the 3 contracts, from the day of upgrading there has been endless issues with my account

On the 1st of December an amount of 1250 was debited off my account which I was okay with because I knew that the first month will be more because I had upgraded, further more the 1st of January comes and mtn debits R1800 off my account, when I had phoned into mtn they said that I have a usage limit on the one cell number I had which I have never had with this number, then I was told a credit will be passed they told me R1700 credit will be passed, I leave it for a few days don't hear anything from mtn then my services gets suspended because of mtns mess up when I phone in to find out that the credit is still being authorized I must pay in R70 no problem i paid in the R70, I then phoned in again as my services got suspend I then followed up for the 2nd time about this query, and I get told my account is in arreas of R2000 and then I said yes but there is a credit that needs to be passed of R1500 now after I have been told that R1700 credit will be passed, I then get another reference number from the call center and that I should call in after 3 days to follow up with the credit I phone in on Thursday 23rd January I got told the credit of 1500 has been passed, I get an sms stating that my account still has got an outstanding amount on it and that my service will be suspended, I called in yesterday 27th January and I get told only R1250 credit was passed which is incorrect, I speak to a manager he said to me that this matter has not been resolved he will ask them to look more into this as I am still getting billed and they will look into the incorrect credit and get them to credit the correct amount, today my services get suspended for the 3rd time within one month I phone in to speak to a manager I got told they emailed a manager he will contact you no one had contacted me since, I phone in again and they said a supervisor said they must reconnect my service and she will sort the issue out without the manager even knowing what is the issue

They have got no communication s****s what so ever they cannot get back to clients they can't credit the correct amounts, I am fed up with this bad service! Do not use mtn!!