This is a ridiculous problem, and you really shouldn't be facing these troubles at all. Modern cars are much more complex than yours. The mechanics you've been visiting, unfortunately, are likely incompetent.
I daily drive a 30-year-old Suzuki. I feel your pain, but I had to do most things myself to get it into a reliable state.
Which city are you located in? Members might be able to refer you to a mechanic that knows what the hell they're doing.
@dani_kk @rajaatta have workshops in/near RWP/ISB.