Asshole Debt Intervention

Mr. Mali phoned me out of nowhere, telling me about cutting debt interest up to 50%. He phoned me. I was curious, so I listened. He then sent me a whatsapp to, I don't know, confirm my number or something. Then phoned again later, and asked for my ID number. I will never give my ID number to someone over the phone, that phoned me, for something I didn't enquire about. Then proceeded to be extremely rude and offensive when i refused to give my ID number.