Indigo Airlines — Misleading and causing fraud to the customer

As soon as I return, I will lodge a legal complaint against Indigo airlines, as their staff gave me wrong information and looting me by charging nearly 9000 extra as well as reducing my trip days. The visa on arrival for Thailand is available for 30 days (also confirmed by immigration people) but the indigo people didn't even check that information but just gave me ultimatum that either I should buy a ticket of earlier date or I should leave!