The P trap of my Ac does not have a vent,like that used to since the AC man changes it and now is clog again is any that someone help me in what to do? Call the AC people I had not hear from them

Can you be more specific? Are you complaining that the AC guy didn't direct the condensate line into a vent stack? Or was there really a vent off the condensate drain line? Give me more details!
In my area the AC guys install a 3/4" running trap,(see image) at the terminal end 5ton prevent bugs from entering your home.
It's against our codes to discharge anything into the sewer, rain water run off, AC condensate drains, water softener recharge or anything else.
If you drain the AC into a plumbing vent the seal in the running trap will evaporate in the winter leaving you with a direct connection between your home and the city sewer or septic tank allowing sewer gas to enter your home. So tell me more about this vent that has you concerned. Back to you, Tom

A/C condensation line has simple, open, vent. On long runs, we usually install several vents to assure good drainage. Yes, for some reason, 3/4" PVC A/C discharge pipe clogs very fast, especially if you don't have proper slope. The more slope you have the better it discharges.

Question: how did you find out it is clogged ?

Milo, In your area where do you terminate the drain? Outside or tied back to aZ house vent? Just wondering, Tom