I find it funny that Denver is going back to NJ now. Unfortunately, it is too late. Even if NJ wanted to come back to the table, by bringing NY to the table, and making it clear that they will do a deal with them, they gave Melo the leverage to not accept a new contract with NJ, which will make sure NJ does not stay in discussions.
Denver has really bungled things. If they had accepted the Nets deal when it was on the table, I think Melo would have accepted the extension, because at that point NY was simply not in the picture, and he would have had to wait until the new CBA to sign with the Knicks (which he doesn't want to do). Instead, they have been greedy, and have lost the best deal on the table, and their negotiating power gets less and less as the deadline approaches.