I accidently ran into the Tony&Guy hair salon recently. It’s indeed in the Yanlord Landmark (LV building, Renmin Nan Lu near Tianfu Sq) like zkoch said. If I remember correctly it was around the 3rd of 4th floor, right in front of u when you get upstairs with the automatic stairway.
Looked sick nice and probably pretty expensive. If I had any hair I would definately give it a shot though.