Worst experience ever with DSL

The worst experience ever. I am being over charged. I have costs that I did not agree with. The consultant told me that I will only be paying a fixed amount. I make that amount available in my account only to find that upon their attempt to debit their inconsistent costs it bounces and I get into arrears. I do not want this contract anymore. It had been a pain every 5th of the month. I regret ever signing up with them. Please help me cancel because their MyTelkom doesn’t even work nor do their email system works. I have inquired on convenient ways to make this ridiculous payment but no one has been responding. The app they referred me to is not helpful at all on my end. I just wanna cancel and pay up whatever is remaining.