AsslaamoAlaikum Mufti Saheb,
الجواب وبالله التوفيق
If a defect is found in the bought commodity or someone bought something without seeing it and after seeing it he is not satisfied with it or does not find it to be of desired standard then in this condition the buyer has the choice to return the purchased items on the basis of finding defect or being not satisfied viewing it. On this basis he can return the purchased commodity and it is Shara’n necessary for the seller to take the commodity back and hence, he has no room for rejecting the return.
Similarly if an item is sold with the choice that if one does not like the product he could return it then it could also be returned in this condition.
However, if the items are purchased after checking and there was not defect found in it and if the buyer wants to return it later then it is not correct to force the seller to take it back. However, if he takes it back out of courtesy then it is his favor, and he will get reward for it. There are virtues mentioned for accepting returns:
واللہ اعلم بالصواب