Airtel — airtel postpaid to prepaid migration

Address:

560037

I am using air tel post paid no (81*44) from last 1 year, because of too much out stand bill every time, i have given request to airtel to migrate to prepaid a month ago, but it was not done. But un fortunatly in a qucik time, i suppose to travel to china country for more than 3 monts, now i am in china country, yesterday my post paid sim lost signal and checked in aitel app, it show as prepaid. I called customer care, they have told it is already converted to prepaid. But with out my confirmation before converting to prepaid, how they have migrated my sim?