Q: How to check if IPHONE 5S is not fake using, Serial No. or IMEI No.

https://selfsolve.apple.com/agreementWarrantyDynamic.do

MY PHONE SERIAL NUMBER IS 01****790

WHEN I CHECK SERIAL CHECK ONLINE IT SAYS AS BELOW WHAT IT IS MEANS  

We're sorry, but this is a serial number for a product that has been replaced. Please check your information and re-enter your serial number. If your information is correct, you may need to contact us.

<Personal Information Edited by Host>

If you entered the number correctly, do not buy that iPhone. It has been

replaced by Apple and then lost/stolen in transit. The iPhone has no

warranty, is not eligible for a reduced price Out of Warranty replacement,

and is disqualified from any assistance in these Apple sponsored fora.

If you have already purchased that iPhone, either return it to the seller

for a refund or do as the message stated contact us

Sir thanks for your reply for the earliest and i have already purchased this phone but i dont understand  that whether this is refurbished or what exactly can you me sir

It doesn't matter what it is. It is not supportable or serviceable by Apple.