Not amused at all

Ive just received an invoice for an installation of a new panic button and a call out fee for a technician to sort out a problem on the unit itself. So my question is why am I paying for these things. Firstly, the panic button was no longer sending a signal to the control room should I have carried on with it in that state? Secondly, to check the unit itself who was supposed to do that if I have to pay for the technician. It would have been cheaper for me to just cancel my subscription with TrackerConnect and start afresh with a new company and I would end up paying way less than what I am currently paying. Please balance me so if a unit is faulty I have to pay for a new one? Whose mistake is it that its faulty. Please come and get your unit and I will start afresh with a new company. Its been great while it lasted these past 5 years.