Worst service

I took out a contract with telkom via mondo almost 9 months ago everything was fine until February whereby I noticed they debited more than my agreed premium nobody called me before this money was taken off my account to explain why. Getting hold of telkom is always a huge problem as you hold on the line until you decide to end the call or run out of airtime. I reversed the premium as I received no feedback. The month of March they debited the correct amount and I thought everything would go back to normal. This month I received an sms telling me my account was in arrears and they I find a debit order which is 3 times my normal debit order. I have been trying to get a hold of you guys to sort this out. Please contact me urgently or else I will reverse the debit order again forcing you to contact me