Tracker response unit useless and no one explains

Last year a call centre agent called This is what I understood 1. They r upgrading my unit to a response unit 2. No installation fee 3. Continuation of the existing contract

What they are claiming now is

1. This is a separate unit, jst a response should I be in an accident, and for me to be able to see where the car is. So I must keep both units and pay for both. 2. There is an installation fee R595 (+-) was debited from my account, (who pays so much for a tracker) 3. This was a new seperate contract.

There is on way I would have agreed to this new unit, it is useless, the app didn't even work I deleted it long ago. This is not on, I can't be paying for something that is useless to me.