When I go to send an email to customers through the "send email" function under the "tools" tab there are multiple duplicate email addresses listed in the "customer" drop down menu.

Each time a customer orders or re-orders an additional email address appears. So when I send an email to a particular customer through the "send email" function they get multiple emails according to how many times they've ordered.

Of note: My Zen Cart is set-up so everyone checks out as guests, no customer log-in or password accounts are created (per my clients request). Not sure if this is creating the duplicates or not.

Can anyone offer a solution on how to correct the duplicate email problem?

Many thanks in advance.