So I rooted my phone and everything worked great on the stock ROM. I made a backup in Clockworkmod and then proceeded to flash Cyanogenmod 10.1.2 Stable. That took just fine but I noticed that I no longer had the ability to make or receive phone calls. Text messages and data still worked, I just couldn't do voice calls. I flashed back to my stock recovery ROM thinking Cyanogenmod was the issue but the problem didn't go away. After some research I discovered that somehow my IMEI had been deleted. It came up as a '0' when I went to the "Status" menu in "About phone". Unfortunately, I didn't make a backup of my EFS folder beforehand (Noob mistake). However, I was able to restore my IMEI by following the directions in this link: ***won't let me link in my first post*** So now I have the IMEI number back in the "Status" menu but my phone still can't call out or receive phone calls. I still notifies me that I have voicemails too, I just can't check them. Any advice would be greatly appreciated.