Creditor's Financial Group Refuses to send information in writing to me. aurora Colorado

This complaint is against "Creditors Financial Group" of Aurora, Colorado and specifically their "representative," (I believe he is lying about that part) Corbin Pedia. Prior to getting calls from him, I received correspondence from Creditors Finacial Group regarding a debt I was paying via a payment plan. I incurred the debt while making a large salary, and after I was laid off and jobless for a year, I could no longer pay it off. 

That portion was all documented in writing, every month. I received 2 letters a month. One in the mail reminding me of the payment I was to make, and another via email confirming they had received my payment. I still made payments along my agreed upon payment plan, until Corbin started calling and the letters stopped coming in the mail. They no longer request payment in writing.

Since he has started calling, I have stopped receiving correspondence from them. I know I am repeating this; it is because this is the most important fact to me. Corbin calls me constantly from a restricted/blocked number demanding I call him back. He also calls my parents, who live in a different city, and leaves them messages demanding they make me call him. He has my phone number. Theirs is on the national do not call list. I just verified that fact 3 weeks ago.  He has no reason to call my family and harrass them. I usually do not answer when he calls because of what an a*****e he is over the phone, that he calls me while I am working, and because he is unreasonable in that he refuses to send me written correspondence.

He leaves angry messages telling me to call him by some unreasonable hour that I can't comply with because it's while I am working. Every time I have spoken with him, he has been rude, insulted me in several ways , and been impolite and called me names, as if he is a child who doesn't know how to properly address a human being. (My theory is that he is trying to beat me down with rudeness until I agree to pay him money I do not have.) His voice makes it sound like he is sneering at me the whole time. 

I have requested multiple times that he send me something in writing showing that I owe "his company" a debt that they are supposedly collecting, but I haven't received anything from him ever or them in the last 6 months. SIX MONTHS.

I no longer legitimately believe they are a debt collection agency or that he represents them. If they had the legal right to collect money, wouldn't they legally be required to send me notification in the mail, especially if I verbally ask for it in writing on a supposedly recorded phone call?

I have no idea how to spell Corbin's last name since I've never actually seen it in writing, but it is pronounced "ped-EE-uh."

There are many other complaints about this company out there, and I do not trust a company or a person who refuses to have something documented in physical mail or even email.

At one point he demanded I "settle" for more than an entire month's pay. I told him that was more than I make in a month, and that it was completely unreasonable, and to please send me something in the mail, and he has never done so.

That was three months ago. Since then, I have never answered his calls. I am still waiting for mail from him that, for some reason, he refuses to send me. This fuels my suspicians that it is not legitimate.

My address was legally changed with the post office almost three months ago, and they probably do not have my new address because the post office has stopped forwarding mail. They can't even be bothered to send me something once a month. There's no way this is legitimate.