We use this:
https://www.amazon.co.uk/dp/B000GEWHNS?psc=1 ( PetSafe 5 Meal Pet Feeder )
and this:
http://www.feedandgo.com/ (bought a while ago when there was an offer... ouch on the price)
They haven't been able tho highjack any of these yet.
Only downside is that they have to eat dry food (sorry kitties)but they haven't complained about that yet (food is food)
but if we go out two days, our best option at the time is to call the cat sitter for one or two short visits so that they are not alone anyway, then they can also eat nice food and not hate us too much on our return.