[mothered]

We already process a replacement with it and its been reported has faulty. At this moment on our end we can't process any replacement with your device

This ^ Is contradictory. Have they, or haven't they processed a replacement? It cannot be both. Also, they really need to work on their grammar- It's very poorly written.

At this moment on our end we can't process any replacement with your device. The only option is kindly refer or contact the store were you purchase this device.  

^ Complete nonsense. If they can't process It on their end, why did they Initially request the following:

I do apologize but our back office is requesting if you could able to provide a copy of the receipt or a proof of purchase so we can proceed for the replacement.

I suggest contacting them and ask to escalate your claim.