Yeah
If nothing else call Customer Support to find out what if anything they put on the account.
While it does seem a little odd it isn't beyond the realm of possibility.
and even 300 for a GS4 refurbished is a steal if it is on the up and up.
What got me is that 150 was needed in cash.
Is also curious if that rep is just being shady and found one out of the system and is trying to make money on the side selling a returned phone or something.