Lightroom Premium not getting activated and showing "Start Trial" message

I purchased Lightroom premium in order to use the selective feature a little while ago. It worked once then but I tried to use it again today and it is saying I am not a premium user. Then, when I continue to "Start Trial" it says that I am "currently subscribed to this" already, as I thought. Therefore I am still paying monthly but am unable to use any of the features that I'm paying for. If there is a way I could fix this it would be greatly appreciated! Thank you.