Sadly I have been down this road before. I put my 300z in for a fault, it kept cutting out. They diagnosed a new cam belt needed. Quoted £86. I left the car with them.
Two weeks later, after several phone calls they were still waiting for parts.
I happened to go into a specialist auto tuner with a friend and there was my car. I said "nice car, what are you doing to it". Mechanic answered full engine re-wire and tune. I said that sounds expensive. He smiled., best part of £700.
4 or 5 days later the dealer phoned me ( they are no longer in business). Car is ready. I had still said nothing to them.
Went in to collect it and unfortunately the mechanic had it out on a test drive.
The manager, who I knew came out for a chat and I explained I was waiting for my car. The mechanic came back and the manager asked where my car was. The mechanic said it was at the auto tuners and they wouldnt release it to Nissan until they paid the bill. :lol:
I held out £86 quid and said heres some money to pay for it, the mechanic said its £680
After numerous phone calls to Nissan they admitted to being horrified and explained the car should have been sent to another Nissan dealer who knew how to fix it.
And gave me nothing