What do I do if a supposed collections company has threatened to have a warrant on me for not paying a loan back 7+ years ago?

I got a call a few weeks ago from some company claiming to be a collections agency saying that I had a quick payday loan that I never paid back. He told me this was all done back in 2007. Now, I did have a couple of payday loans, but they were all paid back in full. He threatened to have a felony warrant put out for me if I don’t pay him $1000 over the phone that day. Being very confused and very broke, I obviously didn't pay it. I have no idea what he's talking about. Even if I had the loan he is referring to, to make small payments to rectify this situation. But I'm not sure, what with all the scams out there, just how legit this all is. How can I know for sure this collections is real and how can I get them to accept my available payment plan if it is real? If they did put a warrant out for me, how do I get that taken care of without jail time? I'm a father with 2 very young boys and I can't leave them and my wife over anything like this. I want to make this right if this is real, but I don't know and I know doing nothing can make things a lot worse. What should I do?