Cancellation of Services but still expected to pay

We cancelled services with the Germiston branch in December 2019, which they were aware of as they promised us extra patrols in our area in order to keep us as clients. (Strange how this can happen only when you cancel) Now they are trying to bully us into having to pay for Jan and Feb 2020 services even though their radio has been disconnected since Dec 2019. My contract was with Top Security which was bought by National. I never signed a contract with National at any point and find it ********* that we must pay for services not provided for. Proof of cancellation in Dec 2019 was even sent through again in Jan 2020, yet we are billed for the two months. Nope sorry not going to happen!