How do I refund the money from my iPhone purchase?

Use this to get the number to contact the Online Store. Contact - How to Contact Us - Apple It usually will take 5-7 business days, and since that was cancelled on April 30, it will probably be a few more days.

If you look at the notice, it states that you have not been billed for the item. If there was a hold on your credit card, that should be removed in a day or two.

See -> Shopping Help - Returns & Refunds 

Returns & Refunds - Shopping Help - Apple