CHARGE FOR DATA NOT USED BY MYSELF

I was admitted to hospital on 15 January 2015 and was discharged on 22 January 2015. In this week of being hospitalised, I was very frustrated due to the fact that I barely had signal within the hospital as I run my own business and I had emails to send out to my clients. I woke up during the nights of 16, 17, 18 and 19 January with a boiling hot phone which I could fry an egg on and the batter ran out so quickly that I had to charge it 3 times a day in hospital. I was given a service number S3-8U12P-PQDE4 via sms and in the same sms said that my query will be resolved within 24 hours. A day later I got an sms saying 7 business days and up to today there are no solution to this. The account came of R8400 odd and someone called me for the first time on 25 February and told me that I must pay and that I used the data. I never used it...how? I use my phone for Whatsapp, bbm and emails... I have had a contract with Vodacom since 2002 and this is the treatment I get? My contract expired Oct last year and in Nov I requested a cancellation to go on pay as you go which was never done... I NEED A SOLUTION PLEASE? I CAN NOT PAY R8400 WORTH OF DATA THAT I NEVER USED!