.....or record the 'phone call yourself. Most mobile 'phones have a record function once a call is in progress. They only have a mobile number for me and I record all calls from cc for my own protection.
I understand and agree with don't answer the 'phone and don't work on G days but sometimes it's unavoidable so either record the call or say "yes, happy to help out if it's legal, please fax me the details" They won't put it in black and white unless it's legal.