My store has been working fine for a couple years. Running version 1.3.7. Now, there is an issue with a single transaction through PayPal.

The customer claims a transaction was made over 60 days ago and now wants a refund because the order was never shipped. The claim is; the money was transferred in PayPal from the buyer to the seller but Zen Cart does not have a record of the transaction.

We checked Zen Cart history and there is no transaction recorded in ZC. We are looking for the transaction in PayPal. In the mean time,...

I want to know precisely at what point the transaction is recorded in ZC.
If the buyer bails out while at PayPal, after confirming the purchase, is the transaction recorded at ZC?
Does the buyer have to return to ZC for the transaction to be recorded?