Shocking service

Went overseas on 21 October 2015, since 23 October 2015, when we landed my international roaming did not work as my account had been blocked. I sent numerous emails from my son's email address but had no joy. My sim card only worked again on 1 December, on my return trip to SA. I was forced to purchase a sim in both Australia and New Zealand as my account was completely blocked. On my return to SA I queried this and was informed that I owed MTN R7794.34, for the month of November. I queried this amount as my sim card was not working, and received a sms informing me on 09.12.2015, at 13.23, that query *** had been lodged. I also went into the Richards Bay branch to query this problem on 29.12.2015, as I received an email with my account details informing me that I owed this amount. I was told this was an automated account, and the amount would not be deducted, as I had lodged a query. Today R7794.34 was deducted from my account, resulting in my account being overdrawn!!!!! Is this the type of service one gets from a company after having been an excellent customer for more than 18 years!!!!! I will most definitely be cancelling my contract with MTN. SHOCKING!!!!!