paypal transactions should have a unique receipt/transaction code which you should be able to reconcile to your paypal account
what I think has happened is that the transaction to the lady has gone through, but whatever BACS transaction Paypal use to get the money you owe them from your bank has fucked up….
I don’t know exactly how paypal works and what laws they operate to. To me it looks like they have fucked up somewhere along the line, such as trying to present the wrong data to your bank maybe in the BACS tape – this is however Paypal’s issue to sort out.
Companies like this don’t like to admit they have fucked up and may decide to swallow the loss (if they have paid the lady but not been able to get money from your bank account) but decide to kick you off using that bank account rather than solve the problem at their end.
You could ask your bank if there have been any disputed or rejected transactions from Paypal and the reason for them. With online trading its not uncommon for merchants (such as paypals) systems to just reject transactions if they are overloaded without them even getting to the bank, but again the companies don’t want to admit there are any issues/risks with their payment system.
