Hi @benzine, let me see if I can help out here.
As @uliwooly mentioned, you have made a previous thread about this. Due to this, I have merged your new thread with the old one.
Have you tried different SIM cards in order to see if it is the SIM card that is malfunctioning? Also, have you tried rebooting your phone in safe mode to see if this is caused by a downloaded app?
If the lack of signal persists in safe mode and with other SIM cards, I would suggest that you try to repair the software using Xperia companion and a computer. Keep in mind though that a software repair will erase all user data from the phone, so it is advised to do a backup before the repair in order to prevent data loss.
Try these measures and let me know how it goes!
