Last month, I had an issue with not receiving the SMS to activate the Add-on (https://community.ee.co.uk/t5/Gaming/No-Xbox-Ultimate-Received/m-p/1363968#M14138). I managed to resolve it with the help of tech support, so I was surprised today when I checked my bill to see that I'm being charged for it even though it was included for 24 months with an Xbox Bundle.
