How to cancel item that says it's being shipped

Hi all how do i cancel somthing that is already saying shipped.

A item i was selling was for andriod and my buyer did not no he has ios. Can i cancel this purchas as it was a simple mistake?

What was the item? Is it digitally sent or physically mailed? If neither of you see the cancel button on the order page then ask support to cancel it by giving the order ID.
https://gameflip.zendesk.com/hc/en-us/requests/new

Thank you😁