This number was trying to sell extended car service.

Same here, they acted as if I had some kind of relationship with them previously. When I told them I'd sold the car, the guy started to try and talk to me about my new car (which does not exist.)

Called my cell phone, which I reminded them was illegal.

this phone number has been calling my house for two days for an extended car service. the number is 516-590-1850. I told them I did not need the extended service cause my car is still under warranty.

This number called my cell phone yesterday and tried to tell me that I need extended service on my car, but I told them that my husband handles what my car needs, so I will talk to him and get back to them.  But they said they would call back at a more convenient time when he is home.  So I hung up.

This number called my cell phone a few minutes ago, but I didn't answer the call this time.  

They are making their rounds again. Called 3x. I do not answer numbers I do not know.
Frustrating!