The Oklahoma Indian tribe that planned to buy DiamondJacks casinos in Bossier City, La., and Vicksburg, Miss., is now suing to get back the $6.25 million deposit it put down on the purchase.
   Global Gaming Solutions, a unit of the Chickasaw Nation of Oklahoma, wants a federal bankruptcy judge to declare it didn't break its agreement to buy the two gambling halls from Legends Gaming, and thus should get the money back
   Legends, based near Chicago, filed for bankruptcy last year citing $298 million in debts. Global had agreed to buy the casinos for $125 million, but the deal fell apart. Global says it didn't break the agreement, blaming Legends' lack of investment which led to a decline in business. Legends, though, says Global is the party that backed out.