My luck ran out on Airtel. The best plan they had in my area was 80GB 4mbps. Of course, last 20% of this 80GB was unusable because of random redirections.
I have had few issues on BSNL after the initial hassles. Calling local exchange has worked. I got a visit within an hour. Filing a complaint on BSNL website also seems to work wonders as the complaints are escalated.
On Airtel, there are no escalations (unless you get lucky with the nodal officer). You end up dealing with the same Airtel Presence team.
I am not saying BSNL is great everywhere. I do not think it is. But at least my local exchange people have turned out to be quite helpful.
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This thread was mainly about automated customer support calls. I got my Airtel connection disconnected in October last year I believe. I still get calls asking me to 'reconnect' that old disconnected number. 10 months after disconnection. And now this automated call to give feedback about the same broadband connection that was disconnected 10 months ago!