Purchased a vape battery from Sunnyside Lancaster that appears to be defective. I bought two identical batteries at the same time and tested both with the same cartridge. One works normally; the other charges but will not heat the cartridge. I returned five days later with my receipt and asked for an exchange, not a refund. The store manager refused and said all sales are final and that I would need to contact the manufacturer. I understand restrictions on returns, but refusing to exchange a defective product sold by the store is not reasonable. Very disappointing experience, especially over a $20 battery.