Earlier today I activated a 1 month gold free trial and could use all of the gold features like going in to parties and playing online.
However now for some reason I have been put back down to silver.
https://account.microsoft.com/services says that I have a gold free trial lasting 1 month
https://account.xbox.com/en-GB/?ref=MeControl&lang=en-GB says that I do not have a gold free trial active and when I try to activate it I get this error: "This payment option is used on as many accounts as it is allowed to be. Remove it from those accounts and try again, or add a different payment option."