|Since the account name can be anything the user chooses, are you saying the account name is your firstname.lastname@example.org. If that's all it is you may not be able to do much since, for example, the first to choose 'john smith' gets to use it. All the other John Smiths are out of luck.|
However if they used your personal information you can probably threaten gmail with legal action if they don't do anything about it. Are they sending emails to people you know pretending to be you?