KNOW THE LIMITATIONS OF THE DO NOT CALL REGISTRY BY GOING TO THIS WEB SITE https://www.privacyrights.org/telemarketing-how-have-quiet-evening-home.
THE NATIONAL DO NOT CALL REGISTRY ONLY COVERS LEGITIMATE TELEMARKETERS AND NOT ALL  SOLICITATION CALLS ARE COVERED BY IT.  The following type of calls are EXEMPT from the DNC Registry:
•    CHARITIES
•    SURVEY RESEARCHERS (So those telemarketers who ask you to complete a survey but then try to sell you something by the end of the call are LEGAL)
•    INFORMATIONAL CALLS
•    POLITICAL CAMPAIGNS
•    COMPANIES TO WHICH YOU HAVE GIVEN WRITTEN CONSENT TO REMAIN ON THEIR CALLING LIST
•    COMPANIES (OR A COMPANY’S AFFILIATES) WITH WHICH YOU HAVE AN EXISTING BUSINESS RELATIONSHIP (EBR)
“A company with which a consumer has an established business relationship may call for up to 18 months after the consumer’s last purchase or last delivery, or last payment, unless the consumer asks the company not to call again. In that case, the company must honor the request not to call. If the company calls again, it may be subject to a fine of up to $40,000.
If a consumer makes an inquiry or submits an application to a company, the company can call for three months. Once again, if the consumer makes a specific request to that company not to call, the company may not call, even if it has an established business relationship with the consumer.”

This web site thoroughly covers the Do Not Call provisions and regulations: https://www.ftc.gov/tips-advice/business-cent ... -provisions-tsr.
The DNC is just a list. A list of people who do not want to be called by telemarketers. Not a machine that automatically smashes them when your number is dialed. It was designed so that you could register and legitimate businesses could and would check the list for people who wished not to be contacted by legitimate business callers. To expect the criminals to observe the list and not call is like expecting bank robbers to not rob banks with a “No Robbing” sign on the door. One has to use a little common sense in understanding that most all of the posts here are complaining about the scammers and those who criminally use your telephone to trick you out of your money regardless of the DNC. They are going to continue calling you tomorrow and the next day whether the DNC exists or not. However, look at all of the post and see how many complain because Walmart or Target has called trying to sell them something over the phone. They all complain about thieves, bottom feeders, scumbags, etc. No list in the world is going to give anyone the total immunity that people think they will get with the DNC registry. Look at all of the companies whom could legitimately dial your number and telemarket you if your name was not on the list, and yet the thousands who could...do not....As far as the DNC list actually increasing the unwanted calls rather than decreasing them, not on my phone it hasn't. All I get are those thieves, scammers, huxters, IRS impersonators, and Rachel that we talk about in these posts.