Good news, Airtel guy called me and patched the call with audio team. The guy from that team clearly understood the issue now. He checked on his home theater while on call and agreed that the surround speakers are producing voice which shouldn't be the case with Dolby Digital. Now he said he knows what to do and he'll work with the broadcaster and do the needful. All these days he did not have an example to show them it seems, since they are not aware of South movies which are available in Dolby Digital. Now this should be resolved soon. I also got his direct contact number and I'll be in touch with him till this closes.