i)Appeal decision. The game allows you to appeal once before
settling the transfer.
ii)Send him out to feeder club. For Belgium/Poland, 3 years is
enough to let him get an EU (European Union) passport. Thereafter,
he can play for your club.
iii)Hope he gets called up by his country and play quite a number
of fixtures in a year, that is, first team lineup. Also, not really
sure about this, but his country must be in Fifa rank 70 and above.
Then when you're confident, offer to give him a new contract. In
the process, the game will also automatically apply a new work
permit for him. If it goes through, the best lor.