You have your old main character named MR.BLA
You want your name to be changed to MR.BRA
You join the server with MR.BRA, then disconnect
You go to your main character page on the website, and change his name to MR.BRA
The namechange is done manually, so you'll have to wait X amount of time. You can still play with you old charactername while waiting.
Once the namechange is done, your MR.BLA has become a lvl1 peasant.
Now, you must join the server with MR.BRA and TADAAA: MR.Bra has all the items, exp and generations MR.Bla had. Only thing he has lost is 1k gold which is the namechange payment.
Now. Where did you go wrong?