You shouldn't be, sounds like the product was rejected because it didn't meet quality standards for receiving (shipper might have sent product that was too ripe, too mature, too young, discolored, evidence of decay, pulp temp, etc.,). This happens fairly often in produce. Talk to your broker to figure out what to do with the rejected product (they'll either have you dispose of it, or deliver to a different warehouse that will accept it, or crossdock facility).
Did they put the rejected product back in your trailer? If so, you should have pictures of it from a couple angles. Also doesn't hurt, while you're in there, to take out one or two of the suspect veggies and slice them open to show internal condition. The goal is to either establish there's nothing really wrong with the product, or that whatever it is would be impossible to detect by an attentive driver standing on the dock with a temp gun.
My gut feeling is 14 cases isn't enough for them to bother trying to resell it and pay you to make a second drop. If my assumptions are correct, and you're dealing with a broker that has a tiny sliver of integrity, it's likely they will tell you to dispose of the rejected product. They'll eat any charge back from their shipper, if any, and you will be stuck trying to find a dumpster to sneak that into. Nobody sitting in a truck stop is going to want a cucumber, much less 14 cases of them.
Be sure to document everything and get instructions in writing. If they tell you over the phone, ask them to repeat it in an email. 30 days from now when they hold payment on the claim, nobody but you will remember the truth of what happened today.