Hi there! I will attempt to assist you today! Please know I am not an Apple employee but just a community member. Please go to Settings>click your name> payments and shipping. Please verify your card is up to date... if your card it up to date, tab out of the payment settings.... then go to "subscriptions" or go under your iCloud button. If you do not see the extra storage in your iCloud... I recommend cancelling and subscribing to the 50GB of ICloud+ again. As for the money you have paid without receiving the storage.. I'm not sure if they will refund you the money you paid without the extra storage, but it is worth a try.
[Edited by Moderator]