Scam, claiming that the phone was theirs...creepy

Here is my story: 

I received a call claiming it was a wrong number from ( 514 586 8074 )

Then right after I got a call from (438 833 3186 ( in french)) really insisting, claiming that they have lost their/my phone.. and that my number was his number too!. I've been having my number since 6 years when I started with Kodoo.  

Here is the weird thing: [b]they knew the model of my phone. They terminated the call, but they claimed ( by text) that they were willing to pay money for the phone. I'm wondering what's the type of scam.

I'm keeping texting with them (Just for fun, I love making fun of  scammers), I'm wondering if they are using social media ( google/facebook) to get the information of the devices. 

I can not track in the forum similar cases like this. Have anyone similar cases? 
Is there something we can do to stop scammers?