u/Demon-of-Razgriz

So I have a 2013 ford fusion, titanium FWD 2.0l 4 cylinder, owner for awhile and every spring I need to get the ac recharged. At this point I had it at 3 ford dealers 2 non dealer mechanic shops and a gm dealer and even a refer diesel mechanic shop for recharge over the years and leak check with dye ever time. No leaks ever found but every year I lose about half my refrigerant with no indication from any place I taken it on where it goes. Recently I just charged using one of those acpro cans out of financial reasons than spend another 150-200 for same thing I did every other year. There's obviously a leak I and everyone else just can't find one. What should I do at this point?