Vodafone — Stopped outgoing calls without any notice or generating bill in middle of the month

Address:

Vadodara, Gujarat, 390022

I have a postpaid account with vodafone from past 3 years, with excellent payment history. I have set up automated payment from my bank account on every bill cycle and before due date. But this time, in the middle of the month without any notice they stopped by my outgoing calls, which affected my business seriously. My concern is how they can stopped it such a way without any notification.