Need help mission glitched out

So i was making my way through tiny tina dlc on tvhm to try get the magic mikssle x4 for my lvl 50 gunzerker was on the quest dwaven allies gotten 3 letters got to the boss killed him go to collect the last letter and glitches out no option to pick up nothing there so im stuck with a broken dlc cant go no further .can someone on tvhm thats on that quest help me was tring to get the items i need to start uvh for the first time.or can someone trade me a magic missle x4 slag lvl 50 so i can start uvh. Plz message me on xbox live GT:PhychoticDrEamz