Sounds like a scam to me. Copy a sentence or phrase from the email, paste it into google, put double quotes around it, and hit search. Probably you will find more details of the scamI have just received a John Lewis e-card worth £120. It seems I sent it to myself. yet I have not ordered or paid for a card. Has this happened to anyone else? I've not opened the attachment in case it contains a virus.
I also have one of these and thought it looked dodgy but checked the JL website and turns out it’s legit (assuming you have the same email as me).