If anybody is still struggling - when you click on add to wallet from the season ticket page on the club website, if it says you ticket is still in the wallet click on remove and you can then re-add the ST to the wallet - you don't need to go back and find the original email.
If you have more...
Yes same with me and when I log into my wallet account it says its already there as well. Seems strange as I still have a guest ticket for the Wolves game in my wallet but my ST and my wife's have gone