It is definitely worth replying to the zendesk ticket that you created (if you haven’t already) and let them know that their suggestion has not corrected the issue. (if the ticket is closed then open a new one and include a reference to the previous ticket by including the ticket number!)
You could also ask them to investigate on their end if they can see if indeed a transaction is pending on your account or if this is just a random incorrect error message.
I hope you get it resolved soon!