Qatar Airways — Service

Hello, I recently traveled to Mumbai on Qatar Airways. My trip confirmation was MBN7UL. I was originally going to leave on the 13th of November and return on 2nd of Jan on a fully paid business class ticket.My father became ill and I had to leave for India in October. In a rush, wanting to leave the next day itself, and in worry for my dad, I googled Qatar airways and called the first 800 number which unfortunately was of a travel agent. The travel agent charged me $500 extra and changed my ticket to an economy class ticket. I was unaware that I was not talking to Qatar airways directly. He then called me 2 hours later and told me that the return was also changed to economy.The rest of my family (husband and 2 children) traveled on Qatar business on 17th of December and they had the same return ticket as mine on the 2nd of January. My father passed away on December 20th and I decided to return to US with my family. I called Qatar airways, talked to the people at the airport and asked to reinstate my business class on return but they did not. They said that I had booked my ticket with a travel agent. I had not. I had booked my ticket with Qatar directly and the travel agent had messed up my ticket. I asked at Mumbai airport too and they denied giving me a seat in business class in spite of paying a full business class fare. They said that the system did not allow it. What appalls me is that in spite of business class seats going empty they couldn't authorize me a seat in spite of me paying for it. With the grief and mental stress I was in, I still had to be seated in economy without my family. I was told that Qatar was #1 airline with the best service. It did not live up to it's name. I want a full refund if you would want me as a customer again.
Vaishali