I discovered that these numbers were from an internet fax. I was doing an internet fax test using hellofax in my google drive. I was testing it by sending a test fax to my fax number but accidentally sent it to my cell phone number instead and since I didn't answer it retried using two other numbers as you posted. I re tested the hellofax in my google drive test using my fax machine number and this time it worked perfectly. Hope this explains what these numbers are... someone sending a fax.
2062990981 called me several times in a row within 10 minutes.. I call screen, so it kept beeping incessantly on my voicemail. It hasn't happened again, but I'm blocking the number, just in case.
NUISANCE CALLS today from the following numbers....
206 299-0981
312 588-7248
These numbers are undoubtedly related as the calls came in back to back (less than 5 mins apart) and at least 3 calls from both numbers, several of them triggering voice mail which captured tones similar to fax machines... I suspect this is a rouse to get you to answer or otherwise react in a way that will confirm your number is active (i.e. calling back to complain). There are other forums who have reported similar activity from one or more of these numbers.