Q: Ipad Mini 2 Cellular Issue

Firstly i bought this iPad from a seller which is the condition isn't brand new (second). My ipad model is Ipad Mini 2 32gb wifi + cellular. Then i have an issue which is the cellular network can't work like it only appears words "iPad" without any logo of searching service or signal bar so this iPad only can use wifi. I've been tried any solutions that i found on Google or Apple which; i should reset network setting, factory reset or update iOS to the latest version (Now my iPad running on 9.3.5) but it still can't work.

Anyone can help me to fix this ? thank you!