Indian Railway Catering & Tourism Corporation [IRCTC] — Difference refund not received for downgraded

Dear sir
I booked e-ticket on18/03/17 for 25/03/17 for hte-bbs in train no 18451/tapaswini exp in 2a/c with pnr no - [protected] status rac-4/5/6 but after charting i with my family was downgraded to 3a/c b-2 50/51/54 that to with 2 upper birth. When asked the tte he did not help me how and what to do, he simply gave a certificate coating (Passenger holding 2a/c ticket but traveling in 3a/c, please do the need). After returning to ranchi i had filed a tdr on 31/03/17 but it was rejected. I asked cro but they said e-ticket refunds will be sent back to the a/c.
Now. Plz check and help me regarding this.
Thanks
Swaroop banerjee
Mob:-[protected]