In this hypothetical scenario we have a business (LLC) that legally purchased phone numbers from a website that sells lists of phone numbers and names.

The business then decides to send 30,000 text messages daily to 30,000 individuals on that list. Each text message, in this hypothetical scenario, provides current stock prices for the major indexes. The individuals that receive the text message are allowed to opt-out by replying with "STOP"

The individuals never provided the business with their phone numbers nor did the individuals provide consent to receive text messages from this phone number.

Is what the business (LLC) did illegal in the United States in this hypothetical scenario? If so how much trouble is the business in? Jail time? Fines? Class action lawsuits? etc?