"In addition, when the telemarketer doesn't have a representative standing by, a recorded message must play to let you know who's calling and the number they're calling from. The law prohibits a recorded sales pitch in a cold call. And to give you time to answer the phone, the telemarketer may not hang up on an unanswered call before 15 seconds or four rings."
If you receive telemarketing calls after you have registered your telephone number and it has been in the registry for three months, you can file a complaint at donotcall.gov or by calling toll-free 1-888-382-1222 (TTY: 1-866-290-4236). You will have to know the date of the call and the company's name or phone number to file a do not call complaint. A telemarketer who disregards the National Do Not Call Registry could be fined up to $11,000 for each call.