Ay2009-10 wrong pan no on tds

dear sir

I had two registered firms. Say Firm X, & Firm Y.

My, principals, a machinery manufacturers, for whom I am serving as SALES AGENT, had filed TDS returns for the AY: 2009-10, 2010-11.  They had mentioned my first firm name X and mentioned  PAN no of Firm Y , on the TDS forms. I had filed IT returns for the both firms without noticing the WRONG ENTRY of PAN no. Now three /four years passed, my firm, unable to get IT refund.

My difficulty now is

Unable to get refund for  Firm X, on whose name PAN no , mentioned wrongly

Local IT AO, told me that Demand notice being prepared to serve, on First firm Say X, on whose name Forms26AS, is mismatching

Now my request is

a) Whether the machinery manufacturer can FILE revised TDS return for the AY 2009-10 & 2010-11

b) what other options there to get Refund and solve the problem

pl advice

thanks

sivaprabu