Reddit reviews CPR V5000 Call Blocker for Landline Phones – Stop All Unwanted Calls at a Touch of a Button - Over 1 Million Sold - As Seen On TV

First of all, not all those calls may be from Yelp. A typical scam is to convince you that someone is calling from Yelp and when you agree to signup, they sign you up in such a way that they take over your business listing. They then hold it hostage by essentially vandalizing it. Another scam is that they are a third-party marketing service that wants to facilitate you getting your business page "for a reasonable fee." Since these scams usually generate out of call centers, they have plenty of available manpower to continually harass you.

Here's what I usually advise businesses to do (mostly generic advice, because Angie's List, Home Advisor, Trip Advisor, etc. all use these tactics. Yelp is often the most egregious):

1. Call Yelp's local business line and ask them directly to stop calling you tel:8777679357. That may or may not help. Yelp has so much turnover that you will probably have to repeat this exercise with the next sales agent assigned to your region.
   
2. Some businesses have reported to have had success with actually taking the call, taking an appointment, and then whatever the sales rep quotes you, simply come back with "we don't have the money for that." This as #1 reportedly stops the calls for a while. Nothing will get you out of a sales rep's hair faster, however, than wasting their time for zero return.
   
3. Do setup your business page on every applicable review service in order to keep someone else from getting hold of it. Then, do absolutely nothing with it. That will eliminate some of the calls because scammers will see they can no longer scam you out of your business listing. You could then do something as simple keeping your phone and address up to date, putting in your business hours, and listing your website as the page for your Google reviews. This is useful because, for example, you won't need someone expensive like me to get your business fixed from being listed as a "tanning salon/HIV clinic" when you run a record store.
   
4. For that matter, make sure the information Dun & Bradstreet has listed for you is accurate. Google, Yelp, and most of the other review sites license their information from them, so making sure the information is accurate can help prevent avoid some of the scams, as false information tends to be overwritten by legitimate information.
   
5. Explicitly tell the rep who calls you "we don't have the money to advertise on yelp so put us on your no call list." This will usually slow down calls for a while.
   
6. Make sure you are on your state's "Do Not Call" list if your state maintains one. Depending on the state, you might find this on your state AG page or a consumer protection page.
   
7. When you get an e-mail from Yelp, click on the unsubscribe or do not contact link on the email if there is one. Usually this will be in small print at the bottom of the e-mail. At least respond with a message to take you off their list.
   
8. If you did #3 & #4, all corporations must have a registered corporate agent. Find their name and address and send them a good old fashioned paper mail, certified mail, return receipt requested notifying them or your local regulations for calling people on the do not call list and that their e-mails fall under the CAN SPAM act and that they you can pursue monetary damage for each email you receive from them (actual law, that's seldom used, and most people have forgotten about).
   
9. If you operate your business on a land line, get one of those incoming call boxes that makes the phone put out the fax identification beep before you answer the phone. Since many of these scams generate out of call centers, their calling system will automatically skip your number. It's old school, but it still works.
   
10. You can also get fancier gadgets for call blocking like this: https://www.amazon.com/CPR-Call-Blocker-V5000/dp/B0191XMBV2
    
11. There are services that will do the blocking for you, such as Call Control.

Every time they call file a complaint with the FTC's Do Not Call Registry

If you can, install NomoRobo on your landline. A part of the program will let you add phone numbers not in the system.

If you can not install NomoRobo you can get a call blocker box like CPR V5000. When they call you just have to push the big red button to block their number.

Weird, this article says ATT DOES offer it (both free version and upsell version) but maybe not in your area?
https://www.consumerreports.org/robocalls/best-ways-to-fight-robocalls/

For landlines (if via VOIP) it looks like you can do Nomorobo (as mentioned in the previous article) as well.

My relative also has a box that initially simulates a "number not in service" signal when it picks up which discourages most of the robocalls. Takes some getting used to from a legitimate caller's perspective though.
I'll see if I can find a link.
Edit - I cannot find a link to whatever device my relative is using but it must be one of the small boxes powered by the phone itself. Sorry.

Apparently there is a whole cottage industry for these things, with this linked one being one of the most popular and well-reviewed. I would do this if the budget allows.
https://www.amazon.com/CPR-V5000-Call-Blocker-Robocalls/dp/B0191XMBV2