I had an issue a few years ago similar, but with a different outcome. My father purchased 8 tickets over the phone for our family to travel to the Caribbean for Christmas week. We all have the same last name. My father maintained control of the tickets until we got to the airport. The night before, he checked us all in online, but there appeared to be an error with my passport. We arrived at the airport and checked in including checking luggage without issue. My passport was checked twice, once at bag check, and once at security. There was no issue. Prior to boarding there was an announcement to present your boarding pass with your passport. I did that, and was flagged. In my last name, there was an I instead of an O. They would not allow me to get on the plane with that ticket. They were willing to resell that same ticket, same seat for me with the correct spelling on my name for $2400. I also had to be the one to purchase this ticket. It was now 60 min to departure, so I did have to act fast, and it was Christmas week, Caribbean. My chances of securing another flight were little. We tried to argue that 8 tickets had been purchased over the phone, why would one name have been spelled incorrectly, an I for an O when the two characters are right next to each other. The phone agent must have mad a mistake. The gate agent was not hearing it. In the end, I handed them a credit card, they charged me $2400. I was issued a ticket in the correct name, for the same seat that I had under the incorrect name. I was able to call CS prior to take off and they said they would look into it. While on the flight, I was refunded $2400 and both tickets were cancelled. While on holiday, through a few e-mails, I was able to get a ticket in the correct name reinstated.
I am very glad that the OP was able to sort it out with only a $75 penalty. But you never know how picky they will be with the name. I passed two levels of screening and it was only caught on the third. I had not even noticed the issue. In the end, the mistake only cost me some added stress. I do now double and triple check prior to booking.