This is not a scam number. Any traveler entering Canada is subject to quarantine compliance verifications. This is the number you are called from for these verification questions. The people calling you are Designated Screening Officers working under the Canadian Quarantine Act and the Public Health Agency of Canada. There are sometimes reception issues with US mobile numbers, thus the silence that can occur on occasion. And yes these agents work on the weekends - Covid doesn't have weekends off
Said they're calling on behalf of the Government of Canada and confirmed my personal information first and asked few questions on my quarantine status.