No information after submitting cancellation of service

I requested cancellation of my land line on the 15th of November online. I received a request number afterwards ( ********** ), though it is now more than a month, and after calling 10210 last week (Wednesday the 13th of December), and still nothing regarding confirmation that the service is cancelled, and that I won't be billed further.

The service is to be cancelled, and I do not expect another billing round to continue, and expect the end of November to have been the last billing month.

Please see to this urgently, otherwise I will have no choice but to take the matter to the ombudsman, for incorrectly billing me, while the service has been requested to be cancelled twice now already.

Regards Sean