If you believe that Uber owes you payment for work you did, your recourse is to sue Uber: a lawsuit is how you get money from people who owe you but will not pay. In the lawsuit you'd have to prove in court that you are entitled to the money--e.g. that you did whatever it is (presumably, driving) that you contend entitles you to payment. Uber can  in turn try to prove either that you did not do those things, or violated your agreement(s) with them, or that there is some other reason why they are legally entitled to not pay you. The court will determine who is right and who is wrong.