Try spraying Oust 3 in 1 - you need to get rid of the smell that the cat is trying to cover up. This is spraying not peeing - it's a boundary marker covering up some other strong scent.
Ladybirder the vinegar is once, maybe twice and the smell dissipates on its own. Don't use it neat. The cat will come again and again if you don't kill the scent.
"WE" didn't, and "I" for one would suggest that if people want to keep animals as pets then they should be held responsible for their actions. I started answering this thread in a light-hearted manner but I have become serious in my comments now, lets hope pet owners take it seriously too.