That is not something they allow the GMs to do. They do not have the option in their tools to just revert your character and grant your account the a char transfer again. Their only option under the system is to refund the purchase which would revert the transfer so you can buy it again for the right character. That can only be done if the account is eligible for a refund under the refund policy. Char services that have been purchased within the past 14 days and NOT USED, can be refunded.
GMs have been known to make refund exceptions but even those are governed by policy and tend to be one time things for the life of the account.
You can re-open your ticket asking if they will grant a refund exception and move the char back. Then you can purchase the transfer again and move the char you wanted.
IF they can help, that is how they are going to have to do it with the tools they have. At least, based on my current understanding of the system. Keep in mind that like anywhere, company policies do change over time so what was done years ago may not be something they do anymore.
GMs never want to say no and do not just sit around rubbing their hands giggling in glee if they have to deny a request. It is far far easier, and more enjoyable, to help customers. If they can’t do it, it is because they don’t have the tools, policy does not allow it, or the GM is not understanding what is being asked for.