After Sukkos Mr. Hadar saw a sign in his shul, posted by Rabbi Posek. “I am collecting esrogim to teach students in my kollel about the laws of esrogim,” the sign read. “The esrogim will be made into jelly afterwards and distributed as a segulah to relevant families.”

Mr. Hadar brought the esrog to Rabbi Posek. As he took it, Rabbi Posek saw a clearly evident black spot towards the top of the esrog. “Is this the esrog you used all Sukkos?” he asked.

“Sure, made a brachah on it every day,” answered Mr. Hadar. “Isn’t it beautiful? Big and yellow and perfectly shaped, with ridges all around! Just has one black spot on it. That doesn’t matter, does it?”

“Actually, the black spot is a significant problem,” replied Rabbi Posek gently. “All the things you mentioned are hiddurim (enhancements) in the esrog, but an evident black spot towards the top renders the esrog pasul (invalid)” (O.C. 648:12).

Mr. Hadar was crestfallen. “What should I do now?” he asked.

“You tried your best,” Rabbi Posek encouraged him. “There’s nothing like learning the laws ahead of time. Now you’ll know for next year.”

“What about the money I paid?” Mr. Hadar.

“Take the esrog back to the seller and tell him that the esrog was pasul,” replied Rabbi Posek. “See if he’ll refund your money.”

Mr. Hadar returned to the seller. “I found out today that my esrog was pasul,” he said. “I’d like my money back.”

“Now you’re asking me?” asked the seller incredulously. “Sukkos was over a week ago! There’s nothing to do with the esrog now.”

“What difference does that make?” responded Mr. Hadar. “You sold me defective merchandise; I’m entitled to a refund.”

“You had a chance to check the esrog all Sukkos,” objected the seller. “If you chose not to check it, you forfeited your rights.”

“I didn’t forfeit any rights; I assumed what you sold was kosher,” replied Mr. Hadar. “Can we consult Rabbi Dayan?”

“Happy to,” said the seller. “But I don’t see any reason to return the money now.”

Mr. Hadar and the esrog merchant went to Rabbi Dayan. “I bought this esrog before Sukkos and was just told that it was invalid on account of an evident black dot,” Mr. Hadar said. “Must the seller refund my money?”

“If the esrog was definitely pasul when you bought it before Sukkos, the seller has to refund your money,” said Rabbbi Dayan. “The merchandise was defective, so the sale was a mekach ta’us (faulty purchase).”

“What about the fact that Mr. Hadar had ample time to check the esrog?” asked the seller.

“That point is relevant to the laws of onaah, mispricing,” answered Rabbi Dayan. “If the aggrieved party, the one who was overcharged or underpaid, had sufficient opportunity to verify the price afterwards and did not do so, he forfeited his chance for redress” (C.M. 227:7-8).

“Regarding defective merchandise, though, even if the buyer did not check he is entitled to a refund, since the sale was faulty from the beginning,” continued Rabbi Dayan. “However, if a common commercial practice (minhag hamedinah) exists not to return after a certain point, the practice is binding” (C.M. 232:3,19; Pischei Teshuvah 232:6).

“What if it’s not clear when the esrog became pasul?” asked Mr. Hadar. “For example, a gouge could have happened during Sukkos.”

“Then whoever holds the money has the upper hand,” replied Rabbi Dayan. “Since Mr. Hadar already paid, we would assume it became pasul in his possession, and the seller would not have to refund the money” (C.M. 232:11,16).

“Does it make a difference whether the psul of the esrog was d’Oraysa or d’Rabbanan?” asked Mr. Ploni.

“When someone sold non-kosher food, there is such a distinction,” answered Rabbi Dayan. “There, however, the customer had the benefit of eating the food (C.M. 234:2-3). In our case, the use of the esrog was to fulfill the mitzvah. Even if the disqualification is d’Rabbanan, Mr. Hadar could not fulfill his mitzvah properly. Therefore the sale is faulty, and he is entitled to a refund.”