it looks, Hotel try to get rid of Expedia commission.
I dont like small hotel in İstanbul, most of them try to take advantage of customer like all other shopkeeper in istanbul. Be aware.
if you visit istanbul try to avoid Sultanahmet's Hotel ( unfortunately most of the turist attraction in this area) and also try to stay in chain hotels.
as long as you are backed by expedia, you are safe to get the refund , but pay the bill by credit card ( best option to get refund from expedia) ( most likely that small hotel will ask you to pay CC comission, it is totally uncommon in Turkey, He try to make you avoid paying by CC, by this way he will avoid any tax payment to government, Government follow all the CC transaction strickly), if you pay by cash get the receipt.

if you are still in trouble, call "176" from any public phone within Turkey make your complain.

by the way I am from Turkey