(Reuters) - Two customers sued Robinhood Financial on Thursday over the online brokerage’s trading ban in GameStop and other high-flying stocks caught up in a retail buying frenzy that forced some prominent hedge funds to cover large short positions. According to court filings in the Northern District of Illinois and the Southern District of New York, the plaintiffs, Richard Gatz of Naperville, Illinois and Brendon Nelson of Massachusetts, seek damages from Robinhood for stopping trading ins GameStop, Blackberry, Nokiaand AMC.