I wonder if they are linked with Sioux City IA number that is actually a Nebraska area code 402-241-8216 and Westerville Ohio number of 614-212-5164. All three of these numbers called one right after the other like a Gatling gun. The caller message started in mid sentence and talked about seize and desist by calling 866-976-9501 (from the Sioux City number). The other two calls did not leave a message.
I don't answer the telephone any more unless the telephone number is displayed and I recognize it. All other calls get my answering message. If it's important, they leave a message. But 99 percent don't leave a message.