«إذا اختلف البيعان وليس بينهما بينة والمبيع قائم بعينه فالقول ما قال البائع أو يتركان البيع»
The Prophet (peace and blessings be upon him) said:
"When the buyer and the seller fall into disagreement, there is no witness between them, and the item sold is still present in its original state, then the word will be what the seller said, or else the two of them abandon the transaction (sale)."
Hadith Referenceصحیح الجامع الصغیر / حرف الألف / 290