Travel Triangle - Travel Triangle not issuing complete refund

I was trying to book a trip to Maldives through Travel Triangle and was contacted by their partner agent from a company called AGA travels. I was given few options in the beginning and I shortlisted one of the options to proceed with the bookig. I was asked to deposit **% of the total invoice amount as security money. After depositing the money, TT was supposed to forwarded my booking to the original resort and they are supposed to confirm it in ** hours which i was informed about in advance. I deposited **k and waited for ** hours. After that it turned out that the resort and rooms i chose were not available. So, i asked the agent to suggest me some other options which they did and I shortlisted another one which got sold out either within ** hours. Now, i was shown some expensive options (**% above my initial budget) so I decided to look for alternatives elsewhere and found a good deal. So i asked TT to cancel my booking and refund the security money. To my horror, I was initial told that TT won't refund a single penny since I was canceling my booking ** days before my travel dates. Kindly note that, I had to request cancellation because the resort that I initial paid for was not available and hence the booking wasn't even complete. I even looked at few other options in the same budget but nothing was available. Since my travel dates were close, I had to immediately look for alternatives. Now, after few discussions with the TT team, they agreed to refund the security deposit after deducting a security fee of *k/person and a convenience fee of Rs *** which sums up to around **** INR. They haven't mentioned in their Terms and Conditions that they will charge this amount in the event when resort is not available. I escalated this to multiple officials within the company including their CEO and Head of operations but couldn't get a resolution. I asked them to refund the undisputed amount i.e ***** INR(*****-**** INR) but they asked me that they will issue refund only when I give them in writing that TT won't be liable to pay anything else after refunding ***** INR. The discussion continued for sometime and despite my numberous calls and emails with them, they refused to refund the amount unless i give a written declaration. I had to unwillingly send a declaration because I didn't wanted my funds to be released immediately so that I can plan my trip. I am submitting this complaint so that I can contest that their deduction of security amount is unethical and illegal. Please find all the evidences attached