Correcting Name
 

Dear,

I just had to booked a ticket yesterday with telephone. Because i used the Transportation voucher. So there was small mistake in the last letter my firstname.It would be "g" instead of "z"
In Ticket : Thai Quoc thonz
In Passport : Thai Quoc thong

I had called back rightnow but they said if i would changed i have to pay 100$ for this.
But its not fair for me . Because i didnt hear clearly that the agent comfirmed "z", i just heard "g"
So what should i do now?

Please assist me on the above matter as this is urgent.

Thanking you in advance for great concern