If you are on Telus or any of their other brands you should be able to configure "Call Control". This feature prompts an unknown caller to type a given digit before the call is actually connected. Filters out 100% of all spam and other automatically dialed calls. Very very rarely I had people miss the prompt and as a result not being able to reach me. We're talking like 2 calls in 3 years. They reached me via email and all was good in the end.