No, the statute of limitations only refers to the ability of a creditor to sue to collect, not whether they may attempt collection efforts. That time limit varies by state. The other time limit is how long a debt may appear on credit reports. That limit is 7 years. Neither limit means that the debt no longer exists or renders it uncollectable unless a specific state law does so.

Please stop calling me . I know this is a scam and will not answer anymore.

They will not stop calling.
Please note that no one at this website is callling you.  Invest in a call blocker
and do NOT pick up on call numbers you do not recognize.

There's not way to stop the calls from being initiated.  Invest
in a call blocker and DO NOT pick up on call numbers
you do not recognize.

Report them:

http://www.consumer.ftc.gov/articles/0149-debt-collection (Threatening civil proceedings with no intent to follow through, or threatening criminal process in order to collect a civil debt is a  violation of the Federal Fair Debt Collection Practices Act.)  The same goes for endless telephone harassment

Also contact your local attorney general

If they continue to bother you,  and you know you do not owe any money, tell them that you know this is  a debt scam and that you are making a complaint to the police for extortion.  Once you get a copy of the police report and they call you again , just read out the  file number and the name of the PD or Sheriff’s office involved.   Tell them you’ll be glad to send a copy to them at whatever address the jack***es are working out of now.

You'll probably have to yell at them and talk over them.
You have to get tuff with these people because,  being akin to thugs, brute force is (metaphorically speaking),  the only thing they understand