I'm sorry to hear that there has been so many problems with the transfer.
As your Bank has said, once the money has left their hands they have very little control over it and any fees that are deducted along the way.
Unfortunately, asking for the funds to be returned will incurr a charge, but I have to point out that during this whole process, its not your Bank receiving the charges or proffiting in any way, apart from the initial charge made by them to send the funds (typically under �30, but depends on the amount).
If all the payment details are correct then all you can do is get your Bank to keep on hassling the intermediary in India.
It may be worth asking for an MT100 form from your Bank which will confirm the payment details and this can be passed on to the beneficiary so he can use it to aid the receiving Bank.