R21 000 for a part that was NOT faulty

My Nissan Micra started having problems holding revs in the morning, particularly on cold mornings and eventually the check engine light came on and the car would not start. I had it towed to Nissan Imperial Parow for diagnostics who informed me that my timing chain was loose and would have to be replaced for R21 000 (timing chains on the kinsey reports are quoted at R800 and my car has done less that 160 000km).<br> <br> As I could not afford to pay this, I picked up my car and had it taken to a private mechanic who had it fixed in half a day for R1500 (turns out it was a misfiring wire in the loom NOT the timing chain). I am rather concerned that I was quoted R21 000 for a part that was not faulty. This can only lead me to two conclusions,1) either the workshop is not able to diagnose cars correctly (which is worrying as Nissan dealers meant to be specialist) or 2), someone in the workshop/parts division is trying to make extra cash off of customers. <br> I have contacted Nissan on several occasions to ask them about this and I have yet to hear back from them (over 4 months). I would like to know exactly what would have happened had I paid for the timing chain only to have the car not start.