Problem with Subscription

Hi there, I am uncertain as to what is happening with my subscription for Realms, on my "settings" screen it says that I have 13 days remaining, but on the realms screen it says 0 days remaining. I thought I had entered payment details and authorised the monthly subscription cost when I signed up but this is not showing on either screen. I am being offered a 1 month free trial again instead. I don't want to lose my realm, what can I do?  Also, I am running windows 10 version but that was not one of my options.