Paying for malfunctioning unit

Where do we start....I tested the panic button on my unit on Saturday 25th of August and no phone call to confirm what is going on.Tuesday 28 August 2018 i messaged them on Facebook only then did someone not knowing too much phone me.The response i got was shocking i must phone them before i test the the unit.....well so now i must phone them in the event of an hijacking and tell them listen i'm gonna press the panic button see if it works.the second response was we see the unit is faulty since January uhm yes it was faulty and it was fixed in January already.I told the lady i don't want the unit anymore as we are wasting money on something that clearly isn't working up to the standard. The car was in for repairs last week also and was without a battery for most of the week and guess what no phone call to ask why the battery is draining.Again on 12 September i had to message them again someone phones my fiance with all kinds of excuses of we must pay R1700 to cancel it(Guess i will take it out myself tonight as the technician showed me where it is installed)then she continues to position the car 2km from where it is actually standing.i won't pay anymore for the unit and not to get it cancelled.We will consult with CPA in this matter.