Find out the model, serial no., find my iPhone status, company it was sold to and its iCloud status.
An example of the data provided:
Model: IPHONE 5S GRAY 64GB GSM
IMEI Number: 358688056503378
Serial Number: DNPLQ452FFGH
Warranty Status: Out Of Warranty (No Coverage)
Estimated Purchase Date: 01/22/14
Registered Purchase Date: 01/22/14
Product Sold by: PHONES 4U LIMITED
Initial Carrier: UK Reseller Flex Policy
Purchased In: GB – United Kingdom
If your request is rejected use the Sold To premium service.