Hello [redacted],
My name is [redacted] from the iTunes Store. I have just finished reading your request, and I understand that you are having issues updating your current soft ware to OS X Mountain Lion.
I'm sorry to hear that you've not yet been able to upgrade to OS X Mountain Lion because the code you received could not be redeemed. I realize that you hadn't in fact used this code already and that you'd like to begin enjoying the features of Apple's latest OS. I'll be happy to assist in getting this resolved.
To be clear, customers who purchase a qualifying new Mac computer between June 11, 2012 and July 25, 2012, that does not include OS X Mountain Lion can upgrade to OS X Mountain Lion for free. To participate in this program you must be entered by August 24, 2012.
I'm sorry to hear that, on redeeming the initial upgrade code you received, you were unable to proceed because an error indicated the code was invalid or had already been used. If your claim is accepted, a valid replacement code will be sent to you by email. There will be no need to submit a new claim. I apologize for any inconvenience in this regard.
Please let me know if you do not receive a replacement code within 24-48 hours, as I'll be happy to look into things further for you.
[snipped...]
I hope this information is helpful, [redacted], and thank you for your interest in OS X Mountain Lion. Please let me know how everything works out. I'd like to be sure that this has been resolved this for you. Take care and have a nice day!
Sincerely,
[redacted]
iTunes Store Customer Support