MTN no customer care

The MTN debit order that went off from my account this month is almost double what it should be, and I am not aware of any additional charges that needed to be paid. I tried calling their stupid call center on "135" multiple times, and following the voice instructions to try and get to a a consultant, and each time the waiting tone plays for a few seconds and then the line goes dead. So then I tried calling the number that is listed for my branch on Google, each time no answer. Then I tried calling back the number that they had called me on a few weeks before, only to hear a voice say that I have insufficient airtime to make a call, even though I have 227 minutes and have been calling other numbers with no problems before or since. As a last resort, I have been mailing the customer care e-mail address 4 times a day since Monday 9 April. It is now Friday and still no answer, nothing. This is absolutely ridiculous, it seems it is impossible to contact MTN