I took my truck in to a Lubestop yesterday for an oil change and ruined my truck, please help!?

When they were done with my oil change they asked me to start my truck up to make sure it was getting pressure. There wasn't and my check oil light came on. Ask me to restart it a couple of times and same thing. While I’m doing this I noticed them scrambling to wipe oil off of the car next to me and thought that was odd. Claimed to not know why my light was on so they're sending me to a repair shop down the road for diagnostics. Made me pay for my oil change before I left and said that when I get a car wash, to bring back the receipt they would pay for it. Asked why I would get it washed anytime soon (its 20 degrees outside) and they said because they got “a little bit” of oil on it and gave me some DEGREASER to spray on it before I get it washed. So I get my truck to the shop and get out to look at the oil on it. All over it!!! When the guy at the shop opens my hood, there’s oil all over everything inside, all over the inside hood and pooling in just about every place imaginable. What a freaking mess. They determine that the Lubestop guys did not use right size oil filter or gasket and it also blew out my censor. They are going to pay for this part and for “some” of the oil to be cleaned up. But they don’t think that I deserve a refund for my oil change and won’t pay for all of it to be cleaned up. Not to mention I am without my car until this is fixed. What can I do about his? And what will all of this oil in everything under my hood going to do to my truck in the long run?