^^ As suggested by archat68, use TNT. But u don't need to hide the fact that it contains a cellphone.
I have sent cellphones many times via TNT and they are very reliable. They'll open the package before you, check the contents and then repack and seal with a TNT seal bearing date/time and other details.
Most of the times I have been charged 151/- rupees excepting a few shipments where I was charged 181/- rupees.
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BTW, do you know that the parcels are scanned at all airports when they are shipped via any courier that uses airways for shipping (DTDC/TNT/FirstFlight almost evenyone these days...).
If they find out that the declaration doesn't match the content, they have the right to refuse the shipment. Also, in worst cases, people from DTDC have filcked the original contents and replaced them with other things!!
Imagine what would happen if you declared the contents as a toy. On scanning, the DTDC employee sees it is a cellphone. He flicks it and replaces it with a toy car!! What can you do under such circumstances??