I texted to several known numbers on Sept 18th and also received a message that a copy of my message when to 1-360-339-9740.  Have no idea who this is or how this happened from my phone.

I've just discovered that my Samsung galaxy S5 under the Set Message Center, reflects an unknown number which has been changed since I first purchased my cell phone number. This is an unknown number to me and well the zip is not of my area, so I was prompted to research the reflected number listed as 360-339-9740. Has anybody gotten any feed back as to where this number could have come from? I discovered this unknown number during an attempt to educate and familiarize myself in order to update phone settings.

I myself noticed this number in my text msg. settings yet I just had factory reset my phone. I have ATT for my wireless provider how about you?

i have att. 360 339 9740 seems to be att message center. i deleted the number restarted the phone and the number came back

Yep. I had this number stored for research and I was an att customer on a business account with "baby momma" the account is in her control. My phone was acting very strangely, and I'm led to believe she's been eavesdropping on my personal affairs.