Apple Pay payment for something I didn't authorise

This morning I received a notification from my bank that a £200 transaction had been made to Adidas for subscription services. I did not make the transaction, so called my bank immediately. They advised that the payment had been made by Apple Pay on an iPad.

I was using my iPad at the time the notification occurred, and absolutely did not make the transaction.

My bank advised that I contact Apple as security had been breached. I spoke with someone at Apple, and the only devices with Apple Pay authorised are my iPhone and iPad. So could not have been hacked. I have changed my apple ID passwords just in case.

I went back to the bank, who advised me to contact Adidas, and give them the transaction reference number. Adidas have no record of the transaction, or a order on my debit card and advised me to file a police fraud report and get back to them once I have a reference number.

My bank have advised that while the transaction is pending, they cannot starter a fraud claim, but they are holding the funds.

I don't understand how this transaction has been authorised by Apple Pay?

Can anyone shed some light?

Many thanks in advance