It’s not Uphold’s problem.
If your BAT is missing, either
- Brave the Browser is not correctly registering your pending BAT quantity but your BAT is still recorded on your PC,
- Brave the Browser has glitched and lost the record of your BAT,
- Brave the Company has initiated a BAT transfer away from your Uphold Brave wallet.
If it’s items 1 or 2, it’s not Uphold’s fault, but Brave’s issue with BAT tracking. If it’s item 3, it’s not Upholds’ fault, because while the wallet is stored in Uphold, Brave has permission to transfer funds out of Uphold on your behalf, and Brave is responsible for any fund transfers out of Uphold. For e.g. if my BAT was stored in my Uphold BAT wallet (instead of the Uphold Brave wallet), it is safe. Likewise, my ETH, BTC in Uphold ETH and Uphold BTC wallets are fine and wouldn’t be lost.
Brave recently had many issues with tracking the BAT quantity (see forums), but they are probably working on it. Probably.