Uhhh... yeah before you could convert Metron Crystal to Metron Dust. They removed that feature after being Blustone 2.0. since Metron Dust can easily obtained by shop, stages, abyss, and manda shop.
Buy the dust from the shop every time it refreshes. You might have to wait awhile if you're trying to t3 everyone but it'll happened. Vs wants it to take forever so you feel like you have to spend manda to speed it up.