Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Ibn Masood (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: If there is a dispute between the seller and the buyer, then the statement of the seller is considered, and the buyer has the choice—if he wishes, he may proceed with the sale, and if he wishes, he may leave it.

Hazrat Sha'bi (may Allah have mercy on him) says that if there is a dispute between the seller and the buyer and neither of them has witnesses, and the sold item is still in its original condition, then the statement of the seller will be considered valid, and the sale will be annulled. And if the sold item has perished, then the statement of the buyer will be accepted and the seller will be required to present witnesses.

Hazrat Shurayh (may Allah have mercy on him) says that if there is a dispute between the seller and the buyer and the sold item is still present as it is, then witnesses will be requested from both. If either of them presents witnesses, it will be given to him on account of his witnesses. And if neither of them has witnesses, then both will be made to take an oath. If both take an oath, the sale will be annulled. And if both refuse to take an oath, the sale will also be annulled. And if one takes an oath while the other refuses, then it will be given to the one who took the oath. And if the sold item is not present as it is or it has perished, then the seller will be required to present witnesses and the buyer will be required to take an oath.

Hazrat Ibn Jurayj (may Allah have mercy on him) says that I asked Hazrat Ata (may Allah have mercy on him) that if the seller and the buyer have a dispute in a transaction, so he (may Allah have mercy on him) said that if they are not straightforward and there are no witnesses with them, then the transaction will be annulled.