Vodafone India — vodafone number which i have been using since last 15 years has got deactivated without any intimation

Address:

Mumbai City, Maharashtra, 400022

Hi
I was out of the country for 7 months and when i came back to bombay i couldnot speak on the the number which i had earlier coz when i tried to refill the money on that number it said the number is not active.
When i went to the vodafone centre they said my number is deactivated since 2006 which was shocking for me coz i have been actively using this number upto march 2017. Please help