Vodafone blocked my services, without any fault of mine

Last month, my 3G, 1GB, Rs. 250 internet pack was activated, it’s usage was over, so I applied for an add-on booster pack of 500 MB, where the operator had told me that from the next bill cycle, add-on will get removed and my original 3G 1GB pack will continue but that didn’t happen and after about 10 days of normal usage, I was informed that my credit limit of Rs. 700 has been exceeded. I told them, that I was informed by the operator that my original pack will continue, so they filed a complaint under my name and they said that they will hear my recorded conversation with the operator. When the bill cycle ended, they said that my bill is Rs. 1147.2 which is greater than my credit limit and blocked my outgoing calls and internet services. I told them, that my complaint was filed 3 weeks ago, they said that it is under-processing, so unless you make the payment, your services won’t start. How can they take 3 weeks to overhear a recorded conversation and decide the case? Why should I pay, without any fault of mine?