1996 Toyota Camry Check Engine Light

I have a 1996 Toyota Camry 4-Door Sedan L4-132 2164cc DOHC 5S-FE that has 134,000 Miles. Recently, a new catalytic converter was instaled and the back struts were changed. The air conditioner passed the test and was filled. Now, the catalytic converter makes a loud ticking sound when I turn off the car and the air condtioner does not work. When the new catalytic converter was instaled, should the oxygen sensors should have been changed being that they were old? What do you think is wrong with the A.C? Thank You!