The way that I translate it, the OP's phone was stolen where he/she works. It is believed that it was stolen by someone that works there. The OP is trying to get the company to provide information about the phone, or the OP is filing a claim against the company to replace the phone. I believe next, the OP is requesting assistance to trace the phone via the IMEI. At least that is my take on it.
OP, you are not speaking to Apple here. We are all users like you. You say the phone did not have Find My iPhone activated. There is no other way to track the phone. Apple does not track phones by IMEI. You are not going to be able to get the help you are requesting here.