Vodafone India — did not activate the plan and huge amount of bill is generated

I have called vodafone customer care on 30th august at 8PM and asked him to activate the international roaming pack of 149 right away and 500rs plan for 2days from 31st august at 4pm as i was travelling to france and was expected to reach by 5PM on 31st august.i dont know if the executive forgot or he intentionally did not activate the plan at 4PM, rather he has activated the plan at 10Pm.i have made approx 20-25 min of calls and used internet for watsapp chat till 31st midnight and received a message stating that my current usage of rs5500 has exceeded the credit limit of 3600 and so i have switched off the internet.The very next day they have barred my number so i have paid 3500 but my number was still not activated.when i have called vodafone customer care they said that an unbilled amount of rs 12000 is generated on your number and you have to pay atleast 80%of the amount to activate your number.since i had high dependency on number i paid 6500(total of 10000) and used the number only for incoming messages(otp from bank).The bill of 16k was generated on 9th in which i have already paid 10k and not used the number after that.i have dropped several mails to them stating that i have already asked customer care executive to activate the plan and he did not do it on time but they are not ready to rectify the mistake and are constantly asking me to pay this amount.i am a student here and in no position to pay such a huge amount for someone's mistake.please ask vodafone to check the recording wherein i have made the request and rectify the mistake and regenerate the bill.this is a clear extortion and harrasment.
Vodafone number-[protected](pune, maharashtra)
Mail:[protected]@gmail.com