Put the cat in a crate and put a container of sand in the corner. Takes 2-4 weeks for the cat to figure it out before you can safely return it to tgevast wilderness of your home. additionally, once kitty seems trained leave it in a larger room with dors always closed. again another month.
Change the litter in both instances 4+ times a day to keep it fresh
thanks for the advice. She will really hate me now
It's also important to note that you cannot be moving the litterbox around. I did that and learned a hard lesson. You hve to put the litter box in one (or two) permanent spots. IF you move the box, the cat will smell the old spot and continue using it. So, if you are going to retrain the cat, put the cage NEAR THE PERMANENT SPOT where they litter box will be. If it's in the closet, put the cage right by the closet. I retrained a 12 year old cat this way. He spent 6 months in the cage and I would let him out only when i was there to watch him. It worked.... he lived till he was 19 1/2 although the last 2 years of his life he was blind....