Airtel — Roaming charges being applied

I have been a customer of airtel for a long time and have held on to my number for long. I normally reside in Chennai and have travelled to Madurai, Where I've been notified that roaming charges would apply when Airtel says it would render sevices across India without any additional charge . I feel that I'm being deprived of what Airtel assures people and I am highly disappointed. I would like Airtel to get back to me as soon as possible.The customer care number is basically useless with an automated message that doesn't provide any valuable information.