I know its kinda obvious but what exactly does it mean? Its an used model but they sent it back to the factory and what? Can I ask to see some certificate or something to prove that it was in fact factory refreshed?
It could mean a number of things, typically it's been used or broken somehow. It might be a unit that was dead on arrival and sent back to the factory for repair, or it failed after being used so the factory repaired it. If this is being sold direct from the manufacturer then it should carry some form of warranty, since the manufacturer will have restored it to full working status.