Like everyone said, make sure to rule out a UTI.

Never use ammonia, because cats think it is urine, and makes them WANT to potty there. That just draws them in.

Get natures miracle, clean up real good in that area. Add a box, and see if that helps

Maybe try a new kitty litter as well.

And we only ask questions, not to be nasty, but to get info to help.
Sometimes we cant decifer language, and stuff over the net. Don't take it so hard, noone means or intends to be nasty, or accuse you of anything.