See my comment below. DO NOT CALL THEM BACK. Look up the real Verizon number on your bill and use that instead: these guys are NOT Verizon and if you give them your credit card number they won't just take the 20 bucks or whatever you think you're paying them.
sounds like it was the Michigan Fraternal Order of Police. The actual police will not conduct fund raisers. 90% of the money raised by the "FOP" (fraternal order of police) pays the staff and execs equipment, etc for the call center, and only a small portion of the rest of the 10% goes to the families of police departments.
Just tell them you're recording the call and they hang up and never call again.