Caller doesn't leave message. Today, I reported to both National Do Not Call List https://www.lnnte-dncl.gc.ca/plt-cmp-eng (for Canada) and https://www.fcc.gov/consumers/guides/stop-unwanted-calls-texts-and-faxes (for USA). Even if your number is on the Do Not Call List, sometimes telemarketing companies ignore the rules. So - the only way to deal with them is to report them. Use the links above to report telemarketers who call you - if your number is on the Do Not Call Registry.
Another three ring / four ring auto-disconnect scammer! They leave no message, and I sure don't answer until the fifth ring assuring me that it's safe to answer. So sad, that's what answering phones has come too!