2004 Dodge Neon Transmission problem/ bcuz of clamp fall

I'm having a problem to understand why my car already have transmission problems can cost me almost $29000. the mechanic place told me it's because the clamp was hold and think it had fall so the fluid come out and etc... they use a lot of mechanic terms. But they ask me if anyone work on my radiator before, so I remember I had an accident i took the car somewhere to get fix and they replace the radiator not the clamp they say but a mecanician told me they have to remove the clamps the change the radiator and they should replace those clamps . So can someone please explain me if this have anything to do with replacing the clamp or not putting it right back in to place can cause all damages to my transmission (make my car not moving)? That will be very helpful to me bcuz I'm trying to get them to fix it if is true it was their mistake.
Thank you!
I can provide picts later not now, but I do have prove the clamp or clamps was hold and fall or left a line or something like that the other mecanician told me