Brought a new iphone copy from Thailand?

Hi, i had purchased new iphone4s copy from Bangkok (Thailand), i had inserted my interntional sim card, it was working perfectly, and even inserted my Indian sim card, both sim cards were working.
I had traveled to other countries too both the sim card were working on it and all the other features too.
When i had landed back to India, it started to show me as invalid sim card and my charger wasn't recognising it, i just went to some local mobile service center, he made the charger problem to get fixed.
The major problem is its showing as Invalid sim card to all the sim which ever i'm inserting.
Can you please suggest me the solution.
It was working in other countries too not only in Thailand, but in diff countries where i had been visiting, but when i came to India, i got as invalid sim, what are the things i can do to make it work back?

Your main problem is that you bought a fake iPhone.