I got the exact same message sent to my cell phone! I looked them up. Found nothing till here and I also reported them on another site. Exact same number that you listed!!
An urgent text message was sent from "[email protected]" saying to call this number. From SantanderMSG: Exact text, Sunday November 6, 2016 at 9:47 pm:
(Your Urgent Attention Is Requested. Ring: 512-521-7973. SantanderMSG])
I got the exact same message sent to my cell phone! I looked them up. Found nothing till here and I also reported them on another site. Exact same number that you listed!!