Unreliable security company

Totally unreliable and avoiding responsibilities. They took over Hi-Risk security in Pretoria and took over the rental radio contract from Hi-Risk. They paid the rental for a few months and then stopped paying without any notification. When I approached them to return all rental equipment, they shrugged it off and refuse to return my equipment as they said the equipment was ******. They refuse to reimburse me or even speak to me to find a resolve avoiding communication. What kind of security company allow equipment under their control to be ****** and then takes no responsibility for it?