Download MTKDdroidtools. Enable USB debugging and connect to the PC via USB.
Give temp ROOT permission.
You may see the IMEI button click on it. And it'll display your IMER
If it's say not recognized your IMEI. Disconnect cable. take out your battery. You'll find the IMEI under the battery. Take note the IMEI.
Now connect back to PC then via MTKDroidTools click IMEI button and change according to your IMEI noted earlier.
Click reboot button and your IMEI will avail via phone setting or *#06#