New-Mac owners, who were promised a free upgrade to Mountain Lion, have taken to Twitter to voice their frustrations with Apple, who has made them wait more than a day to get their new operating system.

The tech giant made consumers a sweet deal last month when it introduced several new MacBooks: Buy any of our computers and we'll upgrade you to Mountain Lion for free once it launches. But what Apple didn't mention was that there might be a wait, and as a result, several eager users who have handed hundreds of dollars over to Apple recently are getting left behind.

Apple asked these new-Mac owners to sign up to receive a redemption code to download Mountain Lion by using its Up-to-Date Program. The process seemed simple enough: Just fill out a few Web pages and wait, then Apple would send you two emails and you'd be ready to download the new operating system. But so far for some users, that hasn't been the case.

Meanwhile, their peers who have not bought Apple computers in the last month are whizzing through to the front of the line, paying $20 and getting their copy of Mountain Lion with no problem.

So how do these affected users handle the issue? Like any of us do in 21st century: They take to Twitter.

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