You can cancel an iCloud storage upgrade within 15 days of buying (in your case that appears to be tomorrow):
Apple have made this as difficult as possible. However two posters have managed to achieve this. Elizellen was able to use Express Lane to get a refund:
However if you use Express Lane may find you cannot proceed without entering a hardware serial number which is still eligible for AppleCare. julia22 managed to find a way round that by phoning them - please see this post:
it gives the USA number - if you don't live there you will have to find an equivalent number from the 'Contact Us' link at bottom right of this page.
If it is more than 15 days since you purchased the storage you cannot cancel it for a refund; you can downgrade your plan as from your next renewal date. Please see
and expand 'Downgrade your storage for the next plan year'.
I called ExpressLane. He quided me to contact Apple Support by email. The reply of email giving me the list of contact no. and ask me to call.
After talking with the Supervisor(suppose to be) and checking my identity, he arranged the refund.
My case is not finish.
Last week, I received email from Apple saying my iCloud storage is full. I checked System Preferences, it became back to 5GB!! Then, I cannot receive email. I called Apple support. They verified my information and gave me back 25GB. However, few days later, I received storage is full email again. Called again, then ok. But today, it backed to 5GB again.
The history repeated.
It really annoying!
The support team cannot solve my problem. They sent email to iTunes/iCloud support. I requested they give me direct emalil, they didn't give me. Few days passed, still waiting their reply.
I was really disappointed this time.