Musannaf Ibn Abi Shayba 13:17

Hushaym narrated to us, from Isma'il ibn Abi Khalid, from Mahmud, the freed slave of the family of 'Amarah, who said: I sold two garments to a man and stipulated to him that if he unfolded one of them, then [the sale] would become binding. He unfolded one of them but was not pleased with it, so he came to return both of them, but I refused him. I disputed the matter with him before Shurayh. He [Shurayh] said: "There is no satisfaction [for him], for the sale is only by mutual consent."