You have done everything you are supposed to do (provided your friend entered your username using the correct case - it's case sensitive) and the email with the code should have been sent out immediately.
The email might have gone into your Junk/Spam folder, please check there. If it's there, please mark it as 'Not Junk' to help with future emails. If it's not there, please email us at firstname.lastname@example.org
and we will sort thing outs for you.