The scam, run by a company based in Mexico, asks exhibitors at trade shows to sign up to its online directory before sending them a large bill.
A number of companies exhibiting at Four Oaks and other shows have been affected, with those inadvertently sending back the forms receiving an invoice for 1271 euros.
Farplants marketing manager Neil Robertson said he signed the forms assuming it was another free entry connected with Four Oaks. "We have quite a few forms to fill in in the run up to the shows, and there’s never been a problem before. The first I knew about it was when I saw the invoice. We’re not going to pay it."
Robertson has written to Expo Guide explaining that he was misled by the form and will not be paying the invoice.