Telkom Contract cancelled but money is still being deducted from my bank account!!!

<p>My mobile internet contract was cancelled in feb 2017 and my final payment was made on 31 March 2017!!!but Telkom is still deducting money from my bank account and each month the amount increases!it started at R199 and it has now reached R597!!!!everytime the customer care agent say they going to escalate my query but nothing changes!!!What must I do to get a simple issue sorted out???????</p>