Hmmmm that's rough
All I can offer is to try gman44 again.
He has always been helpful to me, he could be busy, he's a mod in a bunch of spots.
Any time I've seen people trying to do this they are asked to provide the reason they want the change.
And 3 user names they would want. ( in case the one you chose is already taken)
Maybe those items could help?
If not and they will be pissed at me saying this, go on a computer you haven't used for current user name, and create a new account.
Then immediately tell them you have, and ask them to transfer your encounter reports to the new account and close the current one.
This has a risk of ban, but if done immediately they probably wouldn't.
Seen it before in questions to staff.
Good luck