I had the exact problem on my Oneplus One. I actually broke all but one of my pins in the sim slot. First I disassembled the phone so I could better see the sim slot. I bent the broken prongs up so they would better contact the sim card. Because they are now shorter I had to shorten the sim card by trimming the top of the sim card (the side that is closest to the outside of the phone). Lastly I used a small piece of double faced tape to keep the shorter sim card in place on the sim tray. It worked great. It may or may not work for you.