Payments Sent: Your payment may be unclaimed for one of three reasons:
The recipient has not signed up for a PayPal account and has not yet received your payment.
The recipient has a Personal account (which cannot receive card-funded payments) and has not yet upgraded or declined payment.
The recipient has a Premier or Business account and has chosen to individually accept or decline each payment transaction without a Confirmed Address. If you chose not to provide a Confirmed Address when you sent the payment, then the recipient has not yet accepted or declined your payment.
The funds have been deducted from your PayPal balance. You may cancel this payment by clicking ‘Unclaimed’ and then ‘Cancel Payment’. Please note that all ‘Unclaimed’ transactions will be cancelled after 30 days.
From Paypal web site.