MFC refusing to cancel an extended warranty

Beginning of the week, we sent an email to MFC to immediately cancel the extended warranty that my mother took a day before. Then yesterday I received a response from them saying they cannot cancel the policy since I did not provide the policy number. My response to them this morning was that they need to check the subject of the email as the policy number is on the subject line and we even wrote it at the bottom of the email.

Now few hours later they send again the same email, saying the warranty cannot be cancelled as the policy number has not been stated.

Now this is frustrating as when we were canceling the polocy we responded to the email they sent us that had the policy documents and the policy number as the subject. How is it that they are saying we did not provide the policy number when we were responding to an email they sent with the policy number and the policy documents.

Our worry is that it is going to be month end and the debit order will go off whereas we cancelled it a day after the policy documents where sent to us for my mother's car extended warranty.

Can someone please sort this out urgently.

Regards