How do we stop our new Sun Conure from biting and help him acclimate to his new home and owner?

I recently purchased a Sun Conure from a pet store for my husband's birthday. They told me he was less than 6 months old but no hatch papers were available. The bird will not come out of the cage and has bitten my husband several times very hard.....draws blood. We have tried everything that we have been told to do but he seems aggressive and fearful. Any suggestions??