CAT SMELLS

get a big dog

Prolly hafta evict the cats, scrape out the soil under the crawlspace, scatter lotsa baking soda and/or activated charcoal in the crawlspace area, super-scrub/disinfect/deodorize everything inside the house (using bleach and/or institutional-grade cleanser - and suitable protective gear ... safety glasses, facemask/repirator, gloves, etc), use more baking soda and activated charcoal stashed in corners and cubbyholes throughout the interior rooms, and possibly even dispose of things such as carpeting, drapes, and upholstered furniture.

It might be better to engage the services of a professional - firms which specialize in after-disaster (fire or flood, for instance) cleanup might be worth checking into - they might be able to salvage a lotta stuff you'd otherwise hafta throw out. Prolly turn into a cost-benefit deal; only you can decide what's worth what to you.

Timber makes some good points, so I will try not to repeat them.

I think you bought a house that probably belonged to a "cat lady" (or man) and the no one ever bothered to find the cats a home, so they went feral. As someone who once helped clean up a "cat house" to help a friend "flip it", I can tell you it is close to impossible to get out the smell. We basically gutted the house, resanded the floors (or anything with a wood surface) and re-plastered or put up new sheetrock on all the walls. Painting and resealing the floors helped. No fabric or furniture should be put into the house until all the above is finished, or those items will just soak up the cat stink. Even after we did everything I mentioned you could still get a little sniff of cat piss on a hot summer day. My friend ended up selling the house to woman with 4 cats, we think she didn't notice the odor

If a real estate person lied to you about the house you might have some legal recourse. You might want to check with a lawyer.