Cat almost started a fire!!

I have female cats that seem to be spraying for about the past two years. Last night my husband and I woke up to a crackling noise and noticed our outlet in our bedroom was on fire. He went and turned off the breaker to our bedroom and it went out, but if we didn't wake up our whole house could have been on fire! My husband is screaming at me to get rid of the cats, put them to sleep or give them away. I have been to the vet so many times to get them tested and they say it is not medical. I am at my wits end as to what to do here. I don't want to have to put them to sleep, but our own lives seem more important at this point. My husband also says to lock them in the basement, it is all remodeled, but we rarely go down there, and I don't want to just put them by themselves all day and night. Does anyone use a cat cage? Any other suggestions?

I have a question: Have you spayed your cats? Unaltered cats are more susceptible to problem behaviours than those who have been spayed/neutered.

Regarding the issue of isolating your cats in the basement, have you been asked to keep them down there overnight, or for just part of the day (such as when sleeping for example)? As long as your cats have access to fresh water and litter (and maybe some toys), then it may be more prudent to confine them to one area overnight, rather than letting them run around and get into trouble while you're in bed. They'd probably find this arrangement less objectionable than a cat cage, IMO.

Are they spayed? Indoor spraying is usually due to 1 of 2 things - entire cats, or stress - which cats usually deal with by feeling their territory is under threat and spray-marking it. Using Feliway can help a great deal with stress and territory issues, and if they are already spayed you should be looking to find whatever is causing them to want to mark their territory in such a way as this is not normal behaviour in healthy relaxed fixed adult cats.

I did get them neutered, but the vet told me that if it was after 4 months they still could spray and a lot of people don't know that. I got them from angels for animals, and they did all that before they even let me take them home.

Oh by the way, they are about 10 years old.

My gosh, I am so distraught, they are female, so they got spayed. Sorry for the confusion, but I am not in the right frame of mind!