Weird iPad Air 2 WI-Fi model in a Cellular body

So, my story began when I bought used iPad Air 2 online which was described as Wi-Fi only model (A1566), but as I received it i found out that an iPad has a Cellular model body (SIM-card slot present, black plastic thingey next to the rear camera etc). but it behaved like Wi-Fi only iPad (there were no Cellular settings). I received it with Jailbroken iOS 9.0.2. When I updated it to the latest iOS version (iOS 9.1 by that time), I found out that the Wi-Fi and Bluetooth is no longer working (Wi-Fi button greyed out). iTunes also recognises it as a Wi-Fi only model. (so weird)

So, I have a couple of questions:

- how is it possible to force Wi-Fi to work again with or without jailbrake?

- is it possible toforce iTunes to update the iPad with Cellular version of iOS firmware?

It just seems that the previous owner did something weird with it but why and how?

Any suggestions and advices with be very appriciated.

Thanks.