! If its showing corrupt IMEI (0049...) or no IMEI at all, then you have two choices.
1. Flash a Samsung stock ROM through ODIN or Heimdall by obtaining original Samsung Firmware through Google's help.
If that doesn't help then ...
2) You'll have to contact a professional who'll use a "Box" to online recover your baseband, which works almost always. Boxes like Z3X etc