O.K I found the solution
1. Change the region to U.S (All we know)
2. Re-start the phone within region settings
3. Change the proxy (I used 103.13.29.118 and port 8888)
4. Go to store and tap apps from nokia
5. Problem starts here, we don't find Nokia pro cam or network problem
6. Go back to region settings and select your country re-start the phone don't change proxy or turn it off
7. Go straight to store now pro cam should be visible there
8. Go to store , now pro cam should be visible, when instal window comes tap instal
9. Again it will throw some error now turn off proxy
10. VOILA!!! you are good to go for pro cam
NOTE----- You can also try this without changing your region to U.S. also remember don't use back key while switching between open windows use windows logo to switch. that trick worked for me . let me know your findings with this trick.