I had recently taken my car for its first service. The mechanic had inserted the wrong spark plugs which sent a charge through the computer and burnt it out. The renault dealer has since fixed the problem and got me the new computer on my warranty. They have sent me a bill however for the new spark plugs and the labour of putting the new computer in, which is not unreasonable. I am sending the bill to the mechanic who carried out the initial service, but is he liable for it. In my thinking he should be accountable.