Dear Amir,
First of all i would suggest never provide serial number/IMEI of any device whether it belongs to you or someone else.
Secondly, Pay careful attention to the model number, because this will reveal the origin of the iPhone.
- If the model number starts with M, it was purchased new from Apple.
- If the model number starts with F, it was refurbished by Apple or a carrier.
- If the model number starts with P, it was sold as a personalized iPhone with an engraving.
- If the model number starts with N, Apple provided it as a replacement device for a malfunctioning iPhone.
If you find that your phone was refurbished, it is not necessarily cause for alarm. Apple puts its Certified Refurbished products through a rigorous process that makes them like-new. They clean each unit thoroughly, replace any broken parts if necessary, and change the battery and the outer shell.
Your serial number is in the F category which means its refurbished by apple and its just like a normal i phone. However, the seller i believe will not accept the fact that its refurbished because he is a third party vendor and will like to sell his phone. However, there is nothing wrong with the phone.
You can also verify the serial number: https://checkcoverage.apple.com/