I mean I took the card, the signature but I did not charge the transaction at the end. Then there are no Payment and I would like to contact the customers?
Good day to you, alexchambaron.
Those transactions that we're not processed won't be recorded. Therefore, we're also unable to retrieve them.
You'll want to consider recreating the transaction. Here's an article for your guide: Process a credit card transaction with GoPayment.
Just let me know if you have other questions about GoPayment.