Hello! I was doing some side work for a French client and I was to a French VPN and forgot to disconnect when I started playing WoW. Noticed some servere lag and realized I left the VPN on. I didn’t do much besides sit in Orgrimmar and do a few world Quests.
I know using VPNs in WoW is bannable is there a way to let blizzard know this was a mistake?
Using VPN isnt a bannable offense as long as its consistant and using the same VPN at most your account will get locked requiring u to do a PW reset i believe.
Actually, you are incorrect. VPNs are fine, if you use them all the time to connect to wow. What gets people into trouble is when they suddenly stop using them and Blizzard notices a big change in the connection pattern. That’s easy to fix, sometime by changing your password, and if that doesn’t help, it’s only a ticket away to unlock the account.
Note, having an Authenticator and use SMS protect will significantly reduce your chances to get locked out.
Just to confirm what the others have said, simply using a VPN is not in any way a violation of our policies. It is unsupported, but it is otherwise permitted. 
In some cases our account security system may ask you to verify your log in, often by entering an Authentication Code (if you have an Authenticator), or an SMS Code, or click on a link sent to your email. That’s pretty much it though.