The way things are these days, there is no way that a player gets sold against his wishes. Unfortunately, all the power is with the players, and they can engineer moves but the clubs are stuck for the length of the contract, or until they can make the move attractive enough for the player.
The only conceivable tactic I can see is the 'training with the kids/frozen out of the team' one and pretty much all clubs down the food chain can't really afford that one, both in image and financial terms; and even then, when they can players can just sit back and collect their wages, and not give a hoot.
If, for example, Forte didn't want to go (and I'm not even sure the 'move' to Barnsley isn't only pure rumour), all he needed to do was go a bit slower in the medical, or complain of a twinge or three, and that would be the end of that!