Exhaustive amounts debited! Fail to respond to my email about contract ending

Telkom has absolutely no control over their clients contracts... I recently moved to China and I send money home every month.. One month my account had insufficient funds and my debit order bounced... Telkom without warning or email or any communication debited me three times after... My bank charged me for this twice and when telkom debited.. They took three times the amount I owed! I know telkom has a debit bounce fee but this was way more then the fee...

This is ridiculous.. I have to bear all of telkoms charges and my bank charges...

I then emailed telkom and sent them all my documents in perfect order to cancel my upcoming Contract that's ending... They wanted to be contacted one month in advance.. I sent all documents way earlier... I still haven't been contacted...

Is telkom going to still keep charging even though my contract is over... There is zero communication... The company has poor management.. No control of the customers requests... Continually makes mistakes..

I just want to cancel my contract in peace, I sent all the documents and I need my extra money debited to be accounted for...