Q: How I can get back money if I unsubscribe within 5 days

You can cancel an iCloud storage upgrade but only within 15 days of buying:

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:

https://discussions.apple.com/message/19323996#19323996

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:

https://discussions.apple.com/message/16968425#16968425

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.

Poster 'CCrefund' has posted a method applicable to users in the UK: https://discussions.apple.com/message/21002309#21002309

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

http://help.apple.com/icloud/#mmd602084a

and expand 'Downgrade your storage for the next plan year'.