PayPal didn't receive the money

I have no idea what cause this let me explain. on 04 July, 2007 i had a customer place a order using paypal express that order worked fine.

On 22 July 2007 another customer placed a order using paypal basic, the order was never received by paypal, the customer contacted us after making the order to ask for a conformation e-mail.

We had to tell the customer the order was never processed by paypal so we have no record of payment being made. The customer reordered the item using paypal basic and it worked fine the second time around.

Why is my question?

lextechs:

On 22 July 2007 another customer placed a order using paypal basic, the order was never received by paypal, the customer contacted us after making the order to ask for a conformation e-mail.The most common cause of an order not being received by PayPal (as evidenced by no money being transferred and no confirmation email from PayPal), then either the customer aborted the payment process before final completion, or they didn't use PayPal at all.