Some possibilities:
Restart your phone. This solves lots of problems.
Restart your iPhone - Apple Support
Make sure your phone is logged into your iCloud account (in Settings, tap the top line with your name).
If you are logged in, try logging out of iCloud and then logging back in.
Log into iCloud from a web browser www.icloud.com
Then click on the circle at the top right (that apparently is supposed to suggest a person) and then choose iCloud Settings. This will show you your plan, presumably 50 GB, so you can see if the purchase went through.
Beyond that, i don't know what to suggest aside from going to the Apple Support Page. There is a link there to get more personal support.
Official Apple Support
By the way, this is a forum for Apple users to try to help each other. No one here is an Apple employee, as far as I know, and the company does minimal monitoring. Apple does have a feedback page:
Product Feedback - Apple