Peeling ceiling paint :(

Alright, to get started. This ceiling had just been framed and drywall was hung weeks ago, then sprayed with a primer. This low hanging ceiling has a vent runing threw it. We showed up to finnish it and we got some ez sand up there, sanded and primed; all was good. We put our first coat on and when it dried it had peeled slightly in some areas, no problem we scraped the paint off more ez sand and painted again. this time more paint peeled off and it happened as we were painting. So we tried again and it got worse. So then we tried wood filler in place of ez sand, the paint did the same thing. Now we thought it was the vent in the ceiling screwing us but the paint is peeling all over. I've read the deal on calcemine and latex but theres no calcemine here, and the vent has been turned off. Im gonna scrap it, sprey kilz on it, mud it and sprey more kilz; if this doesn't work im gonna burn the house down. Im runnin out of ideas and im new to the website so I don't know if this is where to post this but here it is. Help is apprietiated. Thanks