Easemytrip.com - Fooled by Customer Service Agents

I went on google to book a flight where easemytrip flashed the cheapest price available for my destination through Vistara in Economy class. When I further looked for an upgrade to Premium Economy, which as per Vistara was readily available, I was told by the easemytrip representative that it is all sold out. I was at first told that for a change of cabin the prices are sky-high & later told that it's unavailable, which was all wrong information as I directly had a word with a Vistara representative who confirmed not only the availability, in fact, the price quoted by her was far more cheaper than what I was told by the easemytrip people. This is such a fraud. I was also made aware that I was issued an Economy Lite ticket which cannot afford any change as it's a separate class that includes the last * rows of the aircraft. I did not just feel helpless but also cheated. Since I booked through an agent, the airline couldn't help me even though I am their Gold Member. It's the worst experience and absolutely unexpected. There was no transparency at the time of booking and I was left with almost no way out. To make it more worse, the representatives and the back-end team both are good for nothing, cause they really do not help. Just get silent when you raise a request.