Greetings Muzi95,
You've come to a great place for help! If your payment was declined both times, it's possible the charges you're seeing are pending and not completed which could explain why the iCloud storage isn't showing. You can verify your subscription on your iPhone by going in to Settings > [your name] > Subscriptions. If you don't see the subscription there, you can also verify the available iCloud storage in Settings > [your name] > iCloud.
As for the payment being declined, you'll find the following article helpful in reaching a resolution for that issue.
If your payment method is declined in the App Store or iTunes Store
If you continue to have issues with the payment being declined after those steps, you'll want to proceed with contacting Apple. You can find their contact options via the links below.
Contact - Official Apple Support
Apple ID - Official Apple Support
Take care!