My cat has always been an outdoor cat but my landlord insisted we change our wooden front door to a thick plastic one and now we don't have a cat flap so she is now an indoor cat.
The moment she became an indoor cat though she has refused to eat or drink anything except Webbox cat treats and they obviously aren't enough to sustain her.
She has always been litter trained but has started to toilet on the beds and floor too.
How can I get her to stop this behaviour?

Get rid of the landlord ,he has changed your cats lifestyle and the cat does not understand why it's being punished

experience

unfortunately if you change a cats territory it will change its habits...our cat recently got diagnosed with diabetes so he had to be kept in the house for 2 weeks...he didnt pee for 4 days because he was so houseproud...then starting going everywhere - dark corners and all that - to stop him going in certain places i mixed up a batch of everything in the cupboard...a mix of carpet cleaner to sort the origional problem out eucalyptus cayenn pepper and a few other spices for good measure...the cat hated the smell so stopped going there...with the cat litter tray your going to hae to keep picking him up and putting him in there he'll get there in the end...just a nightmare getting there!!!lol pets question and answers,www.5d2d.com

and as for food move him onto a professional grade source Eubanka or whatever the vetinary equivilant is...its alot better for them!