i recently bought a used iPhone 6 Plus to replace my iPhone 6. When I went to put my SIM card in, however, it said "searching..." And it wouldn't go last that point. I tried the sim in numerous phones, and it worked fine. I also reset the 6 plus, reset the network settings, and tried different SIM cards. For some reason, it wouldn't work. Has anyone else had this issue? If so, how should I fix it?