VPN has caused enormous problems. How do I delete

Since buying Avast VPN I have had enormous problems, mostly because whenever I want to buy online, sellers ‘see’ me in a different location every time. My bank cards are now always refused and I have to use Barclaycard. NONE of these problems occurred until immediately after installing VPN. What do I have to delete to get rid of it and has anyone else had these problems?
When I checked with the security people at my bank they felt sure that VPN was the root cause.

https://support.avast.com/en-ww/article/Uninstall-SecureLine-VPN

https://support.avast.com/en-ww/articleSearch/?searched=secureline

A VPN hides your location. Banks, etc that expect you to be at a certain location will balk when you are not at that expected location.
It only proves that your VPN is doing it’s job. If you’re on a secure network, don’t use the VPN when you do your banking.
I always file travel plans with my bank before leaving home and then use a location in SecureLine that corresponds with my travel plans to keep me safe when
using open/unsafe wifi.