A similar thing happened to me recently - booked MEL-CNS return for a friend and myself on TT (less than half price of VA - $166 each all up, return, including exit row seats, so too cheap to pass up) and realised after I'd booked and paid I'd incorrectly spelt friend's surname (left out a letter). Rang TT a few hours after I'd booked and got straight through without any hold time, explained my mistake, CSR put me on hold for a minute and came back and said that since I'd called soon after booking they'd correct the name and waive the usual change fee. Great service. Though I don't agree with change fee applying for what is clearly a mistake, not a name change. I have since discovered that I also provided incorrect birth date for friend (I had it incorrectly stored in my phone), so hopefully that won't cause an issue checking in!