It refund of a deceased!

Well, does anybody have any idea about the procedure of getting the IT refund in regard of a deceased person. I filed the IT return of my father, who expired in 2010, for the AY 2011-12 with my mothers bank account details for ECS purpose. But the refund was rejected by the bank as it was in the name of my father. Now they are telling to bring a succession certificate to get the refund. But getting a succession certificate is itself a long and costly affair. So I guess there must be some other procedure to proceed in the above situation. Any body any idea?

SM