Bad service

We took up the price lock. We needed a installer to come out and install the two decoders we have. This happened on the 3 May 2019. Two months later the one decodor does not work. It keeps saying we have not signal. when we call multichoice they say we need to email price lock and they will arrange for a installer to come out. However we must pay for a new installer to come out. Why must we pay for a installer to fix the previous installers mess that lasted 2 months. The price lock department do not even have a telephone number. we have emailed them 8 times in the last week. The mail response is we will get back to you in 24 hours. Well It's been a week already. I really don't know who to turn to any more. i have even posted a complaint on their website with no joy.