The Messenger of Allah ﷺ said, "When the buyer and seller disagree, the word is that of the seller, and the buyer has the choice."
حدثنا قتيبة حدثنا سفيان عن ابن عجلان عن عون بن عبد الله
قال رسول الله ﷺ إذا اختلف البيعان فالقول قول البائع والمبتاع بالخيار
[Hasan] Ahmad reported it (1/466) through Muhammad bin Ajlan with the same wording, explicitly stating that he heard it directly, and Ibn Jarud graded it sahih (625), as did Hakim (2/45) and Dhahabi, while Bayhaqi graded it hasan (5/332). Abu Dawud (3511) and Nasai (4652) narrated it through Ibn Masud with the same wording, and the hadith has many corroborating narrations, including one in Abu Dawud (3512) and elsewhere.