phonecall debt and refusal to give proof of invoice

I got a call from a lady from this company saying i owe my tracker account which i believe i paid off last year through them and i received a cancellation of my account from tracker. I tried to tell this lady this and she tells me tracker does not cancel so i ask her to email me the invoice for when i owe and she refuses saying they dont do that. i ask her to email me from her company what she has so i can have this in black and white as i do not know her or her company and am told i must accept the phone call as proof only that i owe...is that standard practice??? I have never received communication from tracker since they cancelled my account and i settled what i owed.