Jewish-owned stores which sell chametz on Pesach

Hi,

If a Jewish store-owner sells his chametz to a non-Jew before Pesach, but then keeps his store open during Pesach and markets his chametz there, the pre-Pesach sale is still valid and Jews may buy that chametz from the store after Pesach. The owner lacks halachic authority to cancel the original sale, and we don't take the later actions as an indication that the original sale was less than serious.

However: One may not purchase chametz which the Jewish store-owner purchased during Pesach.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 1:149, Orach Chaim 2:91, Orach Chaim 4:95)

Have a great day,
Mordechai