Are chargers and cords that say they are Apple MFi Certified safe?

I didn't realize that Apple Certified and Apple MFi Certified aren't the same thing. I ordered a Type C charger and cable from Amazon for my iPhone SE 2020. At first it worked great. Much faster than the old lightning cable for my old iPhone. But now 2 weeks later, when I first plugged it in, it shows the little lightning symbol like it's charging, but when I check a little while later, the % amount is going down instead of up and the lightning bolt is gone. I really wish Apple would have shipped a charger along with the Type C charging cable, but they only send the cable, which obviously won't work with the old chargers. I guess I should have just bought the charger from Apple, but for the same price Amazon had the charger and a 6 foot cable, which said Apple MFi Certified, which I assumed meant Apple Certified. So my question is, is Apple MFi Certified products safe to use and if so, why won't mine work after only 2 weeks. I did plus in the cable that came with the phone to the charger I bought on Amazon and so far it seems to be charging, so I guess it's the cable that's bad and not my phone (hopefully!) But I don't understand why the cable no longer charges my phone. I also have an older lightning cable from my old iPhone 5c, that still charges that but won't charge my new iPhone SE 2020 at all. I don't understand what the problem is with the lightning able and the Type C cable not working now.