Vodafone India — Unbilled usage amounting to more than rs 33000 in just 2 days!! On my vodafone cellphone number

Address:

Mumbai City, Maharashtra, 400080

I had my number activated on an international roaming plan well in advance before i flew to usa on april 23rd 2016. I even have acknowledgment received on my cell phone that my international roaming was activated. I took my flight on april 23rd 2016. During stopover i just 2 mins conversation with my spouse checking my whereabouts. I never surfed any other websites, nor chatted nor checked my email on my cell phone through out my journey. After landing in usa i saw that my unbilled data usage amounting to more than rs 33000. I was in transit for 23 hours. And i was inside my flight for 19 out of 23 hours of journey with my cell phone switched off. Upon making complaint vodafone's reply was
1) my international roaming was never activated
2) they gave me list of 100 things how cell phone can automatically keep using data even though one is not browsing or chatting or emailing.
I am feeling cheated big time and please help me address my grievance with vodafone.