Are the platform operators obliged to send me the worthless wrapped UST?
Probably they wont entertain the tickets especially if dozens of people are probably engage in the same scenario. They are gonna be tired of handling this when all the things already been fail. But I think they are obliged which should be on the platform TOS as mentioned by Tytanowy.
Im sorry to hear this kind of things. Hopefully you get your funds. They should compensate you with something at least since you also have an insurance for that.