The first time I see someone asking for the BATs on chain to be converted back to vBATs. Nice but that’s not how it works. 
If your BATs are in your Uphold account but you can’t access them, then I’m afraid there not much can be done here. It would on Uphold to take a call.
You should disconnect your Brave Rewards if you haven’t already. You will get to claim your BATs during payouts then. More info here- Uphold no longer serves Russian users. Where to send BAT tokens now? & Important: Uphold no longer supporting countries in Russia, Ukraine, Belarus, and Balkans region.