iMessages not working. Repeatedly error message appears as 'activation unsuccessful' when iMessages are turned on from settings, although an activation charge is cut every time.

I have a technical problem with my iPhone, and repeated efforts to find a solution to this problem on Apple support wbpage does not provide solution to this as it failed to let me select my country-India in options.

My issue is that the iMessages on my iPhone are not working, repeatedly the error message is displayed as iMessage failed to activate, whenever I try to go into Settings Messages-->iMessage to turn iMessages on. On each of my attempt to activate iMessage feature on my phone, an activation charges is cut, but after few minutes it still gives the message 'Activation Failed'.

I have contacted my network service provider and they have stated that this is the problem with Apple, as none of their other customers have such issue.

Please advice me how to fix this issue or provide me an alternative contact on which I can write to for resolution of this problem as I am very disappointed by the fact that 'India' is not even listed in the list of countries in options on support site, and this forbids me to get any help on the Apple website.