Not likely you are being charged for the same thing 3 times. The system does not allow this to happen.
You can only be subscribed to iCloud storage once, so no additional charges can happen.
You may be seeing charges for the same price as iCloud, but that are for something else entirely. How have you identified the charges are all for iCloud exactly?
Any charges from Apple wold appear as "apple.com/bill" on your payment method's statement, but would not identify exactly what they are for. Just because they are the same price does not mean they are the same thing.
The only way you may be charged for iCloud multiple times is if you are the Family Organizer in a Family Sharing group and other members are starting their own iCloud subscriptions which are then charged to you.
How exactly did you stop these iCloud purchases? Seems like you blocked the one an only iCloud charge, and long with some other charge for something else.
You need to allow the charge for iCloud, and actually cancel anything else you don't want or need. Instead of just blocking the charges randomly from your bank or credit card side.
Check your charges by following the steps in the support document linked below and make sure you aren't actually blocking the charge for iCloud.
click here ➜ If you don't recognize a charge - Apple Support
Also check any active subscriptions on your Apple account and cancel any you may not need.
click here ➜ If you want to cancel a subscription from Apple - Apple Support