MTN is the worst service provider

MTN deactivated my Sim card after I paid R1300. I went to MTN southdale and MTN Maponya and non of these branches assisted. I am very disappointed in their service because I was suppose to pay R163 apparently the debit bounced in December, they debited in Jan and no communication was sent about the December debit. Only now end of Feb they stopped my Sim card and sent a statement of billing me R1300. I paid the amount even though I didn't understand why the bill was so high. My Sim card is still in active 7 days now people can't get hold of me.