I do remember Skype being blocked in the UAE when I was there. Didn't know Viber was though.
I have seen adverts for Vonage having unlimited international calling to lots of countries, and for a reasonable price. I know India was on the list, but not sure about UAE, you'd have to look.
edit: Just talked to a lovely girl here who is from that region, and she regularly calls India, Jordan, UAE, and Sudan. She says Vonage is good, but one called NobelTalk
is even better. She said the cost is reasonable ($10 for 300 minutes to the UAE, rates vary by the country you are calling to and from but India is quite cheap in comparison) and the lines are clearer than any other service she has tried.
Hope that helps