I sent my iPhone in for repair with Apple. My last phone was a 4S, so I didn't realize that this SE had a SIM card. When the phone came back, it no longer had its SIM card. I have been trying to get SIM cards to work the last few days to no avail. At the advice of a Boost Mobile store employee, I purchased a BYOD kit and tried all three of those cards. Each time, the phone CSR said that the SIM was incompatible. Another Boost Mobile store employee then advised me to get a SIM card from Sprint. The phone CSR again said that the card was incompatible. Finally, I had phone support send me a new card. That card arrived today, but the phone representatives still claim that it is incompatible. I am starting to think that the problem is that the old SIM needs to be disassociated with the phone first. The phone representative today promised to overnight a 6th SIM, but I doubt it will work. I am beyond frustrated and just want phone service again. Please help!