I’m currently paying $2.99 twice monthly, for extra storage
Do you use multiple Apple ID?
If you have an iCloud subscription, you will receive a monthly bill from Apple, check your email box.
You pay monthly for iCloud storage.
If both invoices are for your iCloud+ plan subscription, compare the invoices.
Check the Apple ID, Invoice Date, Sequence NO, Order ID & Document NO.
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Is there a way to sign up for the 2 TB at $9.99 and then cancel the other two $2.99 charges?
Don't downgrade / cancel the 200 GB, but you upgrade the 200 GB iCloud+ plan to 2 TB.
If you still need help, get support from Apple directly -> Get Support or call Apple in your region see -> Contact Apple for support and service