The only way is to contact support, there's no such thing as minus balance in cryptocurrency if there's any it definitely that wallet provider's fault.
Red-Apple. I had 2500 USD that I swapped to PAX. The ETH balance should be ZERO instead -2500 USD. I need .02USD in ETH to Swap or send the PAX.
I think it is a bug or something from their system. I am just worried if their support will respond. Still waiting..
Their support will still reply, but kind of slow I guess. Maybe, if you want you can just spread this complaint across the internet, maybe that will catch their attention.