10£ were taken from my account

This morning 10£ appears to be withdrawn at an ATM from my account, even though I did not make this transaction, and even though my account had 0£. Now it shows -10£ on my account.

How can this be possible?

Hi there! We experienced an issue on some ATM withdrawals processed again as offline. I can assure you the issue is now fixed and the funds are already back in your account. Apologies for any inconvenience caused.