Oh gosh what a trial!! Hope you've managed to find some kind of solution - think leaving them behind will be best for you mentally anyway as it's one less thing for you to worry about!
I love all of these!!! Our cat Nibbles won't let me near enough for any Christmas cheer - he sees the hat and just seems to know the camera is coming out so legs it!!!
We've recently switched our cat to a new diet - we found a company called Reveal who create high quality cat food. It was a gradual shift because our cat is FUSSY and definitely hates change so we had to do the shift under the radar.
The one we use now is limited ingredient so even if it's not...