Hi. I just bought a secondhand iphone 6. It is all fine and working. The thing is I'm having problems with the sim. There is a black device, maybe something like a sim card reader, and I need to use it for the iphone to read the sim. I can't insert the sim without the black thing directly on the iphone or it won't read the sim. Can someone help me? I want to use my phone without this black thing. And whenever I'd insert the sim without it, the iphone says I need to unlock the sim to the sim carrier, which is globe.