It appears you are uncertain of the short message code you may have received.
Short code text messages use 5 or 6-digit numbers in place of full phone numbers.
Short code text messages typically provide value-added services for brands connecting with mobile customers. Short Code Text Messages:
The code 313131 is from EZ Texting as tikibar1 mentioned. I was able to research the company who will send product demos and coupons to your cellphone number.
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