"and use a sealant."

What do you mean by sealant?

Sealant and AC refrigerant circuit do not go together. I often refer to this as "snake oil" ac repair. Now that this sealant stuff is in there, you aren't going to get it out. Your current system may never work right again. If you put in a new AC and don't replace the line set (the two copper tubes that run from the out door condenser to the indoor coil) if there's any of this gunk left in there it could mess up the new system.

Taking short cuts rarely fixes anything. Anytime your AC system develops a leak, the leak should always be repaired the old fashioned way, repair the leak with brazing solder if possible or replace the part of the equipment that is leaking.

Don't fall for gimmicks folks. If it sounds to good to be true.... you know.

Crazy because the HVAC professionals I had come out said it was a good thing to do since they didn't know if I had a leak. I am in the process of trying to get my money back. Sure it won't happen though.

I was afraid that was what you meant by sealant. Austin Air pretty much sumed it up.