How do you make a paid customer invoice active?

Hi irene18!

From what I'm getting, the invoice was paid then turns to be unpaid, and you wanted to make it paid again. If this is so, you can simply open the invoice and pay it. Then, on the next page select the unlinked payment transaction if it shows. If not, enter the payment amount like paying a fresh invoice.

Let me know if you have other questions in mind.