1)Any חמץ owned by a Jew over פסח is אסור בהנאה; for instance if a store owns חמץ over פסח, its אסור forever 🥯🍞❌
2)If a store says that they sold חמץ but they advertise their חמץ, there is reason to be worried 🤝🧐
3)Can you sell חמץ over the internet? Yes! Because nowadays many deals are made over the internet 🛜🤝✅