How can one verify customer purchase if IAP?

I've got a free app in the Apple iOS store that has paid IAPs.

A customer e-mailed me that he paid but had not been credited for the IAP.

For whatever reason the IAP process didn't work - works for others.

So how can I confirm that this person paid - so that I can enable the IAP manually.

I've got his name, date of purchase and order-id.

Is there something on itunesconnect sales & trends that maps an order# to a product and maybe the sale date...

don't need to know the customer name.

Thanks.