Social media site Twitter(s twtr) has been blasting spam messages to "recycled" phone numbers and ignoring the recipients' pleas to stop, according to a class action lawsuit filed this week in San Francisco.

The lawsuit, which seeks more than $5 million under a federal law that restricts robo-calling, claims that Twitter ignored industry policies about disconnected phone numbers in order to send more marketing messages.

The dispute turns on "short code" technology, which permits companies to send out automated SMS messages. Twitter uses the short code "40404" to send such texts, and to notify users by SMS about activity related to their Twitter account.

According to Beverly Nunes of Massachusetts, she began to receive such notifications from marketing companies via Twitter's 40404, urging her to sign up for "swag bucks"  -- even though she had never used Twitter.

The lawsuit also cites complaints from others who allege they received a flood of Twitter alerts, including ones that woke them up at night. Here is a picture of some of the texts that Nunes claims to have received from two marketing accounts "@swagcodespoiler" and "@dayzdevteam" that allegedly paid Twitter to promote them (I've added the arrow showing the "40404" number):

Twitter 40404

Nunes claims the unwanted text messages stem from the fact that Twitter has been disregarding policies about disconnected phone numbers, which require short code users to monitor a database of disconnected and ported numbers.

As a result, Nunes says, she and others who received reassigned numbers have been receiving Twitter texts intended for people who had the number before them. Her complaint also adds that Twitter disregards replies of STOP or UNSUBSCRIBE to its 40404 number, which are standard codes used by phone users to unsubscribe from SMS notifications.

Twitter did not immediately respond to an email request for comment.

The class action claims that Twitter should pay $500 for each unwanted text message under the Telephone Consumer Protection Act, a 1991 law directed at telephone calls, but which the complaint says applies to text messages as well.

The Twitter lawsuit comes three months after Whisper, another messaging app, was hit by a similar complaint over text spam (or what some might call "growth hacking"). Here's the complaint with some of the key bits underlined, if you want to read it for yourself:

Twitter Class Action Complaint

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