Please raise a ticket at the above.
It could be a while till they get back to you cause they get a lot of tickets during this time of the month.
As to why VPN causes this is because that, many people were using VPNs to view ads not meant for their regions. That would cause getting more ads sometimes if that many ad campaigns in the VPNed region and sometimes ads in some regions are more paying than the one where people live. This was basically a kindof fraud which Brave has took a step to reduce.