Yes but another problem is courier person is not ready to take item back ONCE YOU OPEN IT. Courier person is NOT BOUND either. Because that can lend them in trouble. Once item is opened by buyer and returned to courier, then the seller can CLAIM that it was courier guy who opened the box and took away the item.
They say if you doubt seller then return item un-opened. Or accept the box AS IS at your risk. They are not ready to take opened item back.
Also you have to take care that you open the box carefully so that it can be returned AS IS (if any problem is found). But now opening box, checking mobile, finding fault, re-packaging box... All these itself will take 10-15 minutes. NO COURIER GUY WOULD BE READY TO WAIT SO LONG. They have other deliveries to make.