Oh, great! Now we have to come up with proper code words and code books for everyday life! I', not worried so, some AI solution will help us with that for sure.
1. Ignore voice messages
2. Ask pointed questions to any live caller, esp. one calling from a new number and asking for money...
"In case we get cut off, what phone number can I call you back on?"
If they actually give you a number instead of hanging up (which has NEVER happened in the many times I've used this line), just hang up immediately and call them back, to see if they answer.