Hi there,
Unfortunately, if you sign up using the Google Social Form if will automatically create a username based from your email and Google Account. We do not have the tools necessary to change a username made from a Google Account, and we apologize for the inconvenience.
If you'd like to have your account deleted, please email us at: community@tomshardware.com and I can process your request with out Help Team.
Sincerely,
Caitlin
Assistant Community Manager