Techstination, your destination for gadgets and gear. I’m Fred Fishkin. The battle ranges on against robocalls and scammers. T-Mobile …which launched Scam Shield, a suite of scam fight tools, a little more than a year ago…says robocall volumes have been rising again with many call centers reopening. The carrier’s vice president for engineering services and quality assurance, Grant Castle…says the latest weapon in the fight is called STIR/SHAKEN…