BookMyShow — Refund for ticket cancellation

I have booked a ticker through bookmyshow in PVR screen in Kochi. This was done on 28th October for 29th October 7.05 PM show. I had booked the ticket for 4 people. It clearly stated that i can cancel upto 20 minutes prior to the show. Just to keep the back up i shared the booking code with my wife as well. Apparently this was a split and it did not give me any warning that if i do this, i will not be able to cancel the ticket. Now i am told that i cannot cancel as i have split the ticket. how do i get this resolved and get my refund ?