Charged twice for icloud

Highly unlikely.

The system is set up to prevent this.

Where are you seeing these charges? How do you know they are both for the iCloud+?

Apple charges should appear as "apple.com/bill" on your payment method's statement and as such don't directly identify what they are for there.

Being the same price does not mean they are for the same thing.

Identify the charges by following the steps in the support document linked below.

click here ➜ If you don't recognize a charge - Apple Support

The only you may be charged twice for the same thing, is if you are the family organizer in a Family Sharing and someone else subscribed to iCloud+ in the family group, or you share your payment method with someone else and they subscribed to iCloud+.

You would need to find and cancel the charge on the other persons account in that case.