Remove my number from your system!

I rented an apartment and the rent included armed response from ADT. The contract with ADT remained in the owner of the apartments' name. While living there I struggled for months to get ADT to change my number on their system for the messages they send regarding the alarm. Eventually they changed it, but only after moved to a house in 2016 and were therefore no longer renting the apartment. After several requests to remove my number from their system I still get text messages from them regarding the alarm. Now three years later I get spam calls from other companies asking to speak to the owners of the apartment I rented. My only conclusion is that they got my number from ADT as that is the only place where my number can possibly be linked to the name of the owner of the apartment. I have given up on phoning ADT and asking them to remove my number from their database as this clearly yields NO results.