Subscribe to the Do Not Call Registry at: https://www.donotcall.gov/
There is a bit of lag time but eventually this works for land lines or cell phones. It needs to be updated every so often (perhaps each year) or you will start getting calls and texts again.
Your registration will not expire. Telephone numbers placed on the National Do Not Call Registry will remain on it permanently due to the Do-Not-Call Improvement Act of 2007, which became law in February 2008. Read more about it at http://www.ftc.gov/opa/2008/04/dncfyi.shtm.