Airtel - Outgoing not effective for last two months

I was having a TataDocomo number, which has been known to all my friends and bank etc for more than a decade. As there was a connectivity problem, I requested for porting it to Airtel and they insisted that for a minimum * months, it has to be a postpaid connection. After more than four months of porting on the first of March, ****, I requested it to be changed into prepaid and paid Rs. ***/ as change after clearing all the pending dues of postpaid. From then onwards, there is no outgoing and for the entire March, even incoming wasn't effective. Visits and complaints to Airtel are many but till date no resolution.