Supershield Parrot system faulty 4 times

I had a MK9200 parrot bluetooth system fitted to my new car Purchased from Imperial Ford Cape Town, mid September.It has broken 4 times with only part of it being replaced. each time. The unit freezes and does not work. It has worked for approximately 20 days and been faulty the balance of the time.Each time it has taken up to 10 days to service . I reported this as being faulty for the 4th time on the 21 December asking for a full replacement or complete refund and have had NO response since.