Towing Issues: tow trucks dropped my vehicle, tow truck operator, tow truck driver

Question
Hi, i had my 75 Jimmy towed on Sat 9/5 from Pomona due to the front U joint sounded odd. making noise. so i called AAA and they sent out a flat bed to tow me back home. When they arrived at my home, the tow truck driver was unhooking the vehicle and we were talking about how the drive shaft moved out further that it was when he picked it up. he said you drive shaft or U joint or bushings are out. the Jimmy was not lowered yet and it rolled off the back of the flat bed.. The driver said crap you didn't have the brakes on/.. but they were on. he said wow didn't think that was going to happen.. the Jimmy bounced and the front wheels stayed on the flat bed, at this point he was lowering it. we were in shock.. he looked at the front axle and said yet that's what's wrong. then he said i think you trans is gone. we had a trans rebuilt about year and half ago. so no thats not it.  the insurance  company and tow truck are saying they are not at fault. they said we signed some sort of paper saying we knew it was the trans.. not true... who is at fault and can i sue the insurance and tow company????

Answer
If the tow truck operator dropped your vehicle off of the roll back then they are definitely at fault and any damage they would be responsible for. It does not matter why you are towing a vehicle, if you damage it you are responsible. Please reply if you need any more info.