About all you can do is try a call blocker. Any luck with that? If you have one persistent scammer that is sticking to this number, call blocking should help.
If the scammers keep switching to new and spoofed numbers, you might be able to bock by area code. Other posters may have some tricks, so check other posts on this site. I wish you luck on this, it is a frustrating process, you will have to have some consistent procedures to make progress. As much as possible, you want to avoid talking or interacting with the calls, no pressing 3 to be removed from a "call list", for example.
Called landline. Caller ID displayed Unknown Name. Left recorded message about taking a survey and receiving a free cruise certificate. THIS is a SCAM! They did not leave a message with their name, company name or valid call back number. This way you can not verify that they are a real company and do proper research on them. We do not answer ANY unsolicited call or number we do not recognize. People should realize there is a vast difference between a telemarketer, who is annoying, but does work for a company and a SCAMMER who is looking to profit by whatever lie they can tell to part you from your money and personal information. The calls we receive now are no longer telemarketers. They are all spoofed numbers and criminals. BEWARE! They are on a "phishing" expedition.
Presumed telemarketer. These people (telemarketers) were calling me all day at one point, sometimes 5 or 6 times per day. Different numbers, different ID tags, everything from Child cancer research to Animal charities to Banks and Food kitchens. You name it, they'll use it to get you to answer. I found the best way of greatly reducing these calls is just not to answer. Never answer if you don't recognize the number, and never, ever call them back. They begin to assume its a dead/unused line. In time, the calls slow down and almost stop. I'm now down to maybe one or two calls a month.