Bad service

I upgraded my alarm system last year, for which I had to pay a substantial deposit before they would do the work. Installation took place in November. When I received my statement of account I had been billed for the installation, but the deposit I had payed was not shown nor taken into account.

I have been trying to resolve this since the beginning of December without any success. When I call the call center they either try and put me through to a Credit Controller - who never answer the calls and eventually I have to hang up and call back to the Call Center and have to start the explanation from the beginning again. Or else they tell me that they will escalate to a Credit Controller who will call me back (which never happens).

I have now been trying for close to two months to resolve this issue without any success, or any meaningful response from ADT.