AC issue


Hello! My 2007 V6 started blowing hot air, I took it to my mechanic and they recharged the AC.. the next day, it was blowing hot air again. They had a look and discovered the evaporator and lines need to be replaced. the quote was about $3500. I called Ford to get a quote, it was cheaper but they warned me they usually run into other issues, which will bring up the cost, plus they don't make the lines anymore (they did not look at the car, I only told them what the other mechanic told me).
I am told this is a known issue in some mustangs, so throwing it out there in case someone knows anyone know anyone who in the Halifax area can do this cheaper than that? Its a convertible, so I don't need it, but, for resale value, I'd like to have everything running as it should (and I am looking to trade to something newer next year or so).
An electrical/ac shop should be cheaper than dealers.
Ok, so order the items off RockAuto, but when it comes to the lines they ones listed there all look different, how do i know which one(s) to order? Also do have a recommendation on an electrical/AC shop?