Hidden SMS sending

[Gimmuniverse]

Hello
Android Central people

I am Gimm.
I use * Gionee Elife E7

But I have a problem which occurred about 40 days ago..which is sending unknown message.

I called to my Sim carrier and they told me I have NONE daily packages activated.
And they told me the message my phone is sending to India (foreign country)
Mostly if I restart phone it send messages without my permission. The messages even not stay in sent folder.

Suddenly I get notification which says about 6 rupees deducted from my account.

I tried permission explorer to see which app uses SMS service.but got nothing suspicious.

And I tried resetting to factory default settings. Tried 3 times and still no result.

Used anti virus. No luck too.

What should I do ?
Please help.

Thanks.