You've got to live with it. Deals are deals. The only instance I'd allow renegotiation is when a player voluntarily steps forward to take less money or spread existing money over a greater number of years in order to make room under the cap to bring in other players to increase the team's championship chances. Should have built that chance in. Sit out until the end of your contract.
Deals are deals.
They must be lived with. Remember, I did not ask you to listen. Please read the Fine Print about copyrights, etc.