Bad service. Not able to put through instructions

Mycontract expired at the endof August, which I called the call center to cancel my contract at tgeendof August. Surprisingly not done. Called again in September to cancel once again. The call center agent trying hard to sell me another contract which I declined. October begins and yet again here I am and still my contract hasnot been cancelled. I have to wait 30 days before they can cancelled. I mean seriously I asked for this already in July yet they can't follow a simple instruction.

Tell me what do I have to do to cancel my contract cause the store cannot help as it needs to run by the call center. And they asked me 10 security questions which I found too much.