Hello, I have been using PayPal standard for many years with a web store (osCmax a version of osCommerce). A customer who bought something different in 2018 just tried to place an order for a different item at a different price. He got an error message "this invoice has already been paid". But, there was no payment in the PayPal activity or in my store, only the items he wanted in the uncompleted shopping cart. I'm going to send him an invoice and see what happens, but is there a setting I need to make to stop this from happening? Customer is in Brazil, I'm in the US, and have a PayPal business account.
Thanks for any ideas on what is causing this,
Jon
