What do you do if you don’t get a refunded after you got a reciept for it ?

By 'got the receipt' do you mean the receipt for the purchase, the acknowledgment of submitting the refund request, or a reply saying that you would be refunded ? If the latter how long has it been since you got that reply ? A refund to an account's balance can take a few days, a refund to a credit card can take seven to ten days or so.

It can take up to 10 days for it to appear back in your bank once Apple approves the refund. If it is not there by that time contact the bank and/or Apple about it.

iTunes [Store] Support - Use this form for assistance with account and billing, code redemption, or purchase questions - https://ssl.apple.com/emea/support/itunes/contact.html