I purchased iCloud storage of 50gb a month

You purchased iCloud storage, not phone storage. An iPhone's storage cannot be increased, it is a fixed size.

The difference between phone storage and iCloud storage -

https://support.apple.com/en-us/HT206504

You did not buy more space on the phone, you bought space in Apple's synching service, iCloud. To create more space on the phone, you must delete photos, messages, apps, etc.. be sure to save important photos and data to your computer or an external drive. Check these links...

https://support.apple.com/en-us/HT206504

https://support.apple.com/en-us/HT201656

Video

iCloud storage is independent of iPhone storage. If you need more space on your phone, you will need to delete something. You can’t add storage space to a phone.