Yes i received a phone call regarding my wells Fargo debt from 7years ago. Is it a scheme? ?

Got a call from someone saying they were from DTV Investigation, saying they had been hired to confirm my number and told me there had been allegations made against me and that I needed to write down a case number and call 626 373 8736. It was someone trying to collect on a expired debt that had been written off. It's a collection scam, there is no DTV Investigation licensed in my state or in California which is the area code of the number they give.  Refuse to discuss anything with them. Even though the debt is expired, if you acknowledge owing any money, the debt is reinstated and the 7 years starts all over. They are very slick and calm, acting confident, with good information, but ... they are trying to trick you into acknowledging a debt that is gone.

Did a little more checking 626-373-8736 is a google voice number, how many legitimate law firms or collection agencies use google voice, rather than a business land line? Also DTV Investigation call shows up as being from an "unknown number" ... again why would a legitimate investigation company call from a blocked number. When I do the math, it comes up scam.

"Even though the debt is expired, if you acknowledge owing any money, the debt is reinstated and the 7 years starts all over."  The date of last payment and nothing else determines SOL.  Simply saying that you owe the debt does not reset SOL, and the 7 years you are referring to is the credit reporting time.  California has different SOL's for debt just like every other state. As you can see, California is 4 years written contract and 2 years oral contract:  http://www.nolo.com/legal-encyclopedia/statut ... hart-29941.html
What you are describing sounds like your common criminal debt collector scam trying to scare you into paying money.  It all comes down to one thing, if they are legitimate debt collectors, then they will do the following:
Federal law (FDCPA) requires them to send you a letter (US MAIL ONLY) within 5 days of their first contact that contains their name, physical address, the creditor’s name, and the amount of the alleged debt.  It also must contains “mini-Miranda” telling you that it is an attempt to collect a debt and that all information will be used for those purposes.  The one other important thing that this letter must also have in it is that you have a right to dispute the debt within 30 days of receipt of the letter and if you do so, all collection activity must be stopped until the debt is verified.
Read up on your rights here, get template letters to send and also make a complaint at this government site:  http://www.consumerfinance.gov/
Also file a complaint with your State Attorney General's office.
List of State AG’s offices:  http://consumerfraudreporting.org/stateattorneygenerallist.php