Based on my limited Internet search, depending
on the OS and NetFilter version being used, possible file names
are Netfilter64.sys, Netfiler2.sys and Netfilter.sys. A
file-system search on Netfilter*.sys or Netfilter*.* should
identify if the product is living on the affected PC.
If an installed application using NetFilter is affecting the OPs
VPN service, it is likely a paid application rather than a free
application given that NetFilter is a paid, subscription based,
SDK, IMO.
