Well you can do that if you so desire, but once you pick up that phone & answer the debt then becomes valid even if it is over the statues of limitations, it starts all over again. Don't do answer the phone just let it ring one of these days they will stop. I worked collections for years & they sent me to school to make sure I was up on all the legal laws, so they didn't get in trouble.
This is a company called Denovus Corporation, my guess they are a junk bill collector. They drive me crazy!!! I have never received anything written from them but they do drive me crazy on the phone daily..yes even sometimes 3 and 4 times a day.
Best advice, if they contact you ask for validation of the debt before you pay them a cent. Odds are they don't own your account anyway and they are just like every other bottom feeder trying to steal you of money you don't have and legally they are not entitled to it.