App to manually write a cancellation and refund bill

[Lighthunterxs]

Hey guys, 

we ran into quite a  big problem. As we work with a preorder system a lot of our Paypal customers can`t be refunded over Shopify as the 180days were exceeded. 

As for the billing now the bill in Shopify doesn`t show that there has been a refund. Is there a App to manually write and integrate it into Shopify?