Unhappy Telkom Customer

I have a cellphone contract with Telkom and they were supposed to deducted R1795,62 on the 15th July they went and deducted R1709,23 after having deduct that amount few days later they block my phone! I keep calling their customer service line and they keep telling me my payment has reflected that they’ll escalate the issue with the collections department and I have to wait 5-24 hours until I am able to use their services again. It’s been four days now and I have phoned in and have talked to about 4 agents. I still have not been able to use my cellphone & have decided to call again and find out the update with my account, only to find out I need to pay R86,36 because they deducted R1709,23 instead of R1795,62. I’ve gone through 3 customer care agents and they failed to tell me this? But at the same time whose fault is it that they didn’t deduct the full installment! I’m so not happy with their services let alone their customer care agents.