If it was advanced to Tebow than that is between Tebow and the Broncos. Tebow can pay back that money or the Broncos can suck it up and quit whining. The Jets ain't gonna pay squat I'd bet.
Before the most recent CBA it was a common thing to do with first round picks, and it was always written into the contract that the acquiring team in a trade would reimburse the original team.
Somehow it's the Broncos fault the Jets didn't read the contract?