Budget Rent A Car

Last year Mar 23, 2020 I received an email with Coupon code ... the voucher was given after the cancellation due to the Pandemic episode.
Email read as Rapid Rez Number: ***66T
Coupon is: MUVZ145
Expiration date: 28Feb21

Today I made a prepaid reservation picking up the car at Charleston SC on 2/14/21. Received an email with the Confirmation 35184943US3.
Subject line read: Budget Rent A Car: Reservation Confirmation |MILER| Pick-up date:2/14/2021
Thank you YUKIKA, your car has been reserved.
I told the Reservation clerk my name was spelled wrong. She said I won't be able to pick up the car with the wrong spelling. Called Cust Svc to correct my name to Yukiko Miller, but Supervisor John Hernandez was unable to change the prepaid reservation. He said he could cancel the reservation then rebook but he won't be able to use the voucher and it'll be $132 higher than pre-paid amount. I asked him to just email me the explanation of 'proof' the confirmation is for MILLER. But he wouldn't ...