iCloud storage does not add storage onto your device. It adds storage into Apple's cloud storage system, here you can save backups and photos. There is no way to convert this to device storage. You are aware of this right?
To view and manage your iCloud storage go here - You should have 2 TB of iCloud Storage.
Please remember this is a monthly subscription and you will be charged every month, you continue to receive this storage.
Whenever you make a card transaction, the funds are taken on a hold, so it will appear with your bank as pending, this normally lasts for a day or two where the funds are "reserved" until the merchant takes your money, it seems this is what has happened here.
For example, you could use this to save storage on your phone, by keeping low quality/resolution photos on your phone but keep the high-quality originals in iCloud.
Take a look at this help article for more info Set up and use iCloud Photos – Apple Support