Mitsubishi Repair: o-rings leaking on airconditioning, jenny jenny, o rings

Question
1998,Mitsubisi, Mirage 1.8L. My car was leaking out the airconditioning where the tubing goes through the wall of the car . The guy that worked on it said it was the o-rings. I have been back 8 times, and paid to " fix it " and it still leaks, they even ordered the o-rings from mitsubishi. He had put on oversized o-rings thinking that would work, when the mitsubishi ones came in and it was still leaking he said one of the oversized ones was still not leaking so he replaced the other oversized one with a mitsubishi o-ring. It still leaked out. Now he says he should replace the tubing that goes up to where the o-rings are and wants more money, an additional $283.   I live on disability and am really upset. I wondered about him using two different sized orings on it, wouldnt that cause it to leak ? I'd appreciate any suggestions you may have. Thank you, Jenny

Answer
Jenny,
If your mechanic saw that the proper sized o-rings did not help, they should have stopped wasting time with oversized o-rings and replaced the tubing immediately.  I've replaced A/C components with o-rings I bought at my local hardware store, so your mechanic should not have wasted all your time and money messing around with Mitsuishi o-rings.

The problem was most likely with tubing all along, and they should have been able to determine that sooner.  You may have luck getting some sort of compensation from your mechanic on the price of replacing the tubing.  But if you're fed up with your mechanic, I would recommending taking your car to someone else to diagnose and fix it properly.
Good luck!