Find another dealer!!
A reputable independant dealer will probably be more willing to spend the time DIAGNOSING and fixing the car. Receiver replaced 3 times in 12 months? I'm guessing they haven't been finding/looking for the root of the problem...
Whereabouts are you? England?
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black