A suggestion: If you have a police whistle to, just blow it into the earpiece of the phone several times. Might help. I'm thinking of doing this next time get one of these "important calls"....I do have a whistle. Another idea: answer and then say "Officer, this is the call I'm wanting traced" ....that might get them to hang up quickly.
I receive several calls a week, thank goodness not in one day. I usually don't answer calls from numbers I don't recognize. My home phone is forwarded to my cell, so this time I simply added to my call reject list on my cell. It has worked in the past with other annoying calls.