Also got a text from this # on my cell phone that I barely use, and certainly never entered it on a website. Message to call 800-571-4439 for a $200 Walmart rebate voucher. I called (used *69 to block my number) and got no answer. Definitely will not reply to text. As Al above writes, they start by requesting a $4.35 processing fee. It's got to be a scam and possibly an issue for FTC (Federal Trade Commission) to look into since this is a San Francisco area code doing business across state lines. They're probably harvesting credit card info to use and/or sell.
I was calling the number back to complain about the 10 PM text messages, but I got the recording that the subscriber is not taking calls at this time, also. I'm just going to call my phone carrier and have them block the number.
Received text message "Thanks 4 Visiting Our Website Call 800-571-4835 To Claim Your $200 Walmart Voucher! Reply STOP 2Unsub or Call 415-513-5459 2 Unsub Now" from this number.
Two of these scam text messages in one day!! After receiving a number of others in recent weeks. So annoying.
Make sure you report it to your phone provider as well as to the FCC (http://esupport.fcc.gov/complaints.htm) as soon as possible so that they start doing something about it!