The lock turned really hard on our trailer when we first used it and I was worried that the key would bend or break. With some lube on the lock it loosened up and gets better with use. I also spent a lot of time turning the inside lock lever back and forth. That helped loosen it up too.
If it really is on the verge of breaking I would take it to the dealer or a lock smith and then take the bill to the dealer.
2011 Eagle 330RLTS with just about every option.
Dodge SRW 1 ton Cummins powered.
I was born with nothing and I still have most of it left.