Im hoping this is system issue and the bit that adds the to up to the card lost connection with the finance system and generated an automated email. Here is the salient part of the email from TFL:
We automatically topped up your Oyster card (number xxxxxxxxxx) with £10.00 pay as you go credit on 08 February 2024. However, we were unable to take payment from your credit or debit card.
Please pay this outstanding charge within three working days otherwise your Oyster card may be stopped.
