I had very experience for past few years.
Enabling hindi jokes for hindi not known person(They have refunded)
Enabling local tariff for STD users, I am from other state(I have free local call at my home and office). I have enabled Rs.99 plan for a month without any intimation they have changed the plan Rs.125 local time is increased with STD charge.(Twice they changed plan for few months, till not refunded)
They will not respond immediately and force as to pay money with penalty for their late reply.
Many times I have raised request to talk to higher management but never did it for past few years. Every 6 months once I will get feedback call but their wont be proper closure.
Frequently need to check the bills.
I was checking for good service provider.