Need my Refund

I gave them the notice to cancel my contract with them as it came to an end, of which I did receive an email with a letter of acknowledgment from them. on the letter, they've promised to refund me from February as my tracker was not working and they couldn't give me a test report. I have not yet received my refund and they are continuing debiting from my account. I have tried to call them and they told me, they will come back to me but they still don't. Send an email to the lady who helps with the cancellation and she promised to come back to me and she hasnt.