If you read the linked email exchange with Rossi, it appears that while she may have collected some data for him, the method and process used does not conform with the details included in the paper.

It seems no one can provide receipts (which is bad! due to reproducibility), and since Ariely's name is on the paper and Rossi's is not, the onus is on him to have kept that documentation. He asked that Rossi at least corroborate the details described in the paper, and she refused to do so saying that it didn't align with her memory or her standard procedure at that time.