Twitter has been slapped with a lawsuit for sending text messages to numbers that are no longer associated with the social network.

Twitter, has attracted heat over sending spammy text messages to telephone numbers that are no longer associated with the social network. The micro-blogging service has failed to monitor the numbers that have been ported out or disconnected before sending promotional messages and also gave no heed to requests to stop notifications. As a result, the social networking company has been slapped with a class-action lawsuit filed in San Francisco this week.

A Massachusetts woman filed the suit against Twitter that alleges the social network sent promotional text messages to recycled phone numbers. People who never signed up for a Twitter account or authorized the social network to send unsolicited messages are getting the texts simply because the phone number was previously used by someone who had an account with Twitter and opted for such texts, according to a PC World report.

Beverly Nunes of Taunton, Massachusetts, got her new number in November last year. She received several text messages from "40404," which according to a complaint filed in the court is a SMS short code for Twitter. Nunes is seeking more than $5 million in compensation in the lawsuit, which claims Twitter is in violation of a federal law that restricts robo-calling.

Twitter, like many other companies, uses "short code" technology, which is used to send automated SMS messages. The social networking uses the short code 40404 to notify users about the activity on their Twitter accounts.

Twitter said, "We believe these claims are without merit and will vigorously defend ourselves against them," GigaOm reports.

The report adds that the class actions suit claims Twitter should pay $50 for each unwanted text message under the Telephone Consumer Protection Act, which extends to text messages as well.