Yes, Samsung HM1350 does have call reject button.
No but you will get USB Cable with the unit.
To connect Samsung HM1350 with your smartphone, please follow the below steps.
01) Make sure that your smartphone's Bluetooth is switched ON.
02) Switch ON your Samsung HM1350
03) Now search for the visible devices on your smartphone
04) select Samsung HM1350
and you're done.
No. It does not have.