I went through something similar. We did try some different foods, in case something wasn't agreeing with her. When she would eat what we tried for about 3 weeks and then quit and staunchly refuse even with tough love (like 8 times), I eventually moved her to raw. That solved all of our problems.
I would prefer to feed a good kibble, to be honest, but this is what has worked. I've kept a kibble in the lineup, and with the recent nutritional DCM info coming out, I switched that to Pro Plan. She's getting several meals of kibble in a week. I've done my research on the raw, but I consider the kibble hedging my bets, plus it's easier for travel.