According to The Consumerist:

"If Sprint telemarketed you after you told them not to call you again, you could get $500 for each time they rang you up, thanks to a recent class action settlement.

Sandra L. Palmer v. Sprint Solutions, Inc. alleges that Sprint telemarketed customers across the nation after they had opted out of telephone solicitations. Also, the suit says that Sprint made telemarketing calls using a robodialer that played a pre-recorded message to customers living in Washington State."

The settlement site can be found here.