Make My Trip Pvt Ltd - Cancelled the Airline Ticket by Saying Alternate Flight Not Available and didn't got the refund as w

I had round tip booking from Mumbai to Mahe, Seychelles (**th Feb - *th March). On *st march makemytrip send me a message that return flight got cancelled and you will have to cancel the ticket as alternate flight was not available. Due to limited network availability i was not able to confirm the same with airline carrier. Because of that i had to cancel the ticket and rebook the same on urgent basis at very high prices.
After coming back when i contacted the airline they told me that they have provided alternate flight to customers and i observed the same at airport too and told me they have no clue why MMT said that to you.

Secondly, the total cost of ticket was Rs **,*** with effective cashback of Rs *,***. The refund i am getting is only Rs**,***, they are deducting the complete cashback and are also charging the convenience fee for the cancelled part.
Thirdly, I didn't got any fare break - up as in how much i paid for Mumbai - Mahe and for Mahe - Mumbai, so there is no way for me to validate whether the cashback they are giving to me is correct or not.

Forthly, I have followed up with them multiple times with the matter, and it has been ** days till now and i am only hearing that they will get back to me and have not received my money yet

If you feel my complaint is valid do klet me kniw, i will attach the relevant documents too, along with cancelled ticket, chat where they told me to cancel the flight and so on.