Had the free trial (family), cancelled the free trial as i didn't want it to roll over, was just testing deezer to see if i like it.

I do. 

I want to keep the plan, but i an unable to manage the subscription. On the manage my subscription page it says "family plan ending on *date*)  but I cannot change anything and there's a little padlock in the top right corner.

Have tried login to website and tried via app. 

Cannot change it!