Threatening clients

Good day, I received a service from MyOwn ISP from May to November last year. My Last payment was 03.11.2021. I asked them to deactivate my port from 1 unit and activate the port to the unit right next door. They provided me with false information and advised me that I Have to cancel the first line and activate the new line. I was advised by the Fibre provider that there is a port in the new unit with the appropriate hardware. They would just have to de-activate the old port and activate the new port. They have also advised me that I do not have to pay a cancellation fee and that after 6 months I have no obligation to MyOwn ISP or Atec System Solutions. They clearly stated that I have to refuse to pay any amounts being demanded. Now I was handed over to Alliance Call Centre. They are now threatening me with legal action and that my employer will be involved etc. This business is completely unprofessional and they do whatever they please. Now the case has been handed over to Alliance Call Centre. I receive threats from them on a regular basis. It is now at a point where they are threatening me to take legal action and contacting or visiting my employer to set up a Garnishee Order I assume. The also threaten that I will receive a subpoena to appear in court.