My original charger was lost & I had to use other store bought chargers. Thing is, those chargers would only work for a little while & none of them could fast charge. It was like my phone was eating up chargers. So I broke down & bought a charger from Samsung explicitly for my phone. Wow, fast charging again. But guess what... now it won't fast charge & says I need the charger that came with my phone. What is wrong????