Cleartrip is not that clear with GCs

My experience with cleartrip was not that smooth and the customer care is not clear at all.. I was trying to book a trip using gift vouchers. The total price of the flight was 3357. After applying the third gift card they will show that we have redemmed 3595 (which is 238 rupees higher than what is shown) and in the next page they will ask for 225 conv fee. Initially i thought that the price may have gone up but I checked with cleartrip and other sites. I contacted them and they didnt know what was happening. They are saying that there is nothing wrong with the charges. I tired, with other flights too and too my surprise i could find that they were charging high fare; may be thinking that we wont notice. Finally I booked through ixigo and got a better discount. My request you guys is do not buy cleartrip vouchers for flight booking. Picture below..