call your carrier and tell them that this number keeps texting you, they will deal with it, I had the same thing, and turning it off was not an option either lol
you must have entered your number somewhere, maybe filling out a survey online or buying a product from a shady company. Call your carrier asap before they sell/use your number for other products/ervices
If you have an Iphone, you can download the app iBlacklist, then you enter the phone number, I did it with a compagny that kept calling me everything evening, work fine.