Well, if you're not a lawyer, then you're a judge.
Anyway, regardless of anything else, you need to get actual facts.
You need to locate the source of the leak on your vehicle.
There are so many possible places, we can't go any further in our diagnosis until we get that key piece of information.
Then, you need to get the shop to tell you what caused the leak at that location.
If its an actual seal point on the transmission for a rotating part (think torque converter main seal, or half-shaft output seals), then you will want to know why those seals leaked. Was it a nick on the shaft that caused it? What caused the nick? Is that a part they replaced when they rebuilt the transmission?
Or is it a connection point that leaked?
Maybe the dipstick tube cracked, and fell off.
Maybe the cooler line was loosened by a client of yours who didn't like the job you performed for them.
Maybe its your neighbor who hates the fact that you keep suing them because their oak tree leaves keep landing on your property, and you are charging them for cleanup.
We don't know what happened to your truck.
By the sounds of it, you don't either.
Get the word from your shop, come back to us, and we can then give you our non-professional opinions.