SAR & Associates Try to scam, collect a debt Plantation Florida

Received a letter, didn't pay any attention to it because I knew I didn't have any debt owed.  Then days later received a call while I was in the shower no message, did a reverse search saw the company name after a few searches, called the number back, spoke to this woman tried to tell me that she is collecting on a debt from 2012 for a online payday loan that I got and never payed back, while I had her on the phone I looked at both my bank and credit report didn't see anything. 

I told her I would research this further and call them back, she said she would put a hold on my account, I told her to do what ever she needed to do I don't care but I'm not agreeing to anyone or anything until I researched it.  End up researching it did not see a single thing on my bank statements from 01/2012 - 03/2012, nothing on my credit reports about any loans.  Called them back told them to never call me again and I researched and did not see anything.  she told me I needed to send them something stating that to remove my name and I asked what and she said the burden was on me, which doesn't make sense.

I said yea whatever don't call me again.  didn't receive a call until today some guy talking about he making a second attempt to collect a debt.  Do not fall for them they are trying to scam, they have some info to almost seem legit.  but I'm not stupid and I never borrow and not pay back.  I will block their number and never speak to them again, they do whatver they feel they need to do, I have my statements from the time they said proving I never received any payday loans.