Telkom has suspended my business phone, email and wifi

Telkom has suspended and blocked my business landline, emails and internet with the story that my account has exceeded my credit limit. It has taken a week to get the reason and I am told that my account is nearly R6000 for next month but they cannot tell me what the charges are for because the bill has not been raised yet. My account has never been more than R900 in a month so I assume there is an error. I am loosing business over the busiest time of the year with no way of resolving the issue. I phone up to 5 times a day and I am told my problem has been escalated.