I have received email confirming I have submitted/changed my upgrade offer which I did not.

If you did not request this change, or if this request appears to have been made by an unauthorised person, please click the cancel button in the email and log in the Upgrade Bid platform with your booking reference and family name to cancel the offer. However, if you have submitted bids for multiple passengers, then any passenger listed in the booking will be able to log in and amend or cancel the bid, after which you will receive a notification informing you of the change. Please note that once you have submitted your credit card details to bid for an upgrade, you will not be required to re-enter those credit card details if you wish to adjust the bid amount at a later stage.