Resist calling back numbers like this: most likely they are phishing for "live" phone lines, those with humans at the other end, and in particular, humans who are curious enough to call back an unknown number. You might have opened yourself up for a lot more spam/scam calls.
Consider a call blocker that will work with your phone system. You can register an offending phone number in your call blockers, and you'll never hear from that number again. Google CALL BLOCKER and find one that works for you.