Go for ADL if you dont hav any other option, even a internet cafe nearby. They are only interested till they get our amount , after that no service. Most of the time there will be no connection ( in their words , line complaint). If we get connection , dont worry , it will get disconnected with in 10 mins at most 2-3 hrs. But they have a 24*7 condolence and comfort help line. they will promise you that everything will be fine by tomorrow. But every day have a tomorrow.
So the complaints will be there. I am calling them daily atleast once for last 2 months. One day one engineer came and at that time there was connection, so he returned happily, but issue is still open. I have a prepaid connection 3000 Rs. I will stop calling them by October end( else I will lose phone charge in addition to 3000 Rs) and think that I have give 3000 Rs to a beggar.
May be this is their issue in trivandrum , my advice is don’t go for prepaid for big amounts