incorrect PAN number on TDS -- please help to correct it

problem : incorrect PAN number in TDS Implication : we did not get TDS refunds from income tax department. status : deductor says, it is not possible to issue new Form ( since they are not willing to file revised TDS returns ) Request : what is the process to correct the same & receive refunds ? cause of the problem: My mother was the proprietor of our business ( sub contract works ). Our deductor has used her PAN number on form 16.unforunately our mother expired and my father became the proprietor , but we forgot to update the PAN number to the deductor -- due to which we had incorrect PAN number in our FORM 16.