Indian Railway Catering & Tourism Corporation [IRCTC] — AC Not working in Mumbai Express

Hello,

I booked ticket at Mumbai Express from Mangalore to Thane on 25th April 2017.
PNR:- [protected]
Seats:- B3- 58/57/ 60 & 61
The services provided in train was average, however AC for the specific berth was not working.

I with other passengers raised complaint against it to TC and Ac mechanic, however we didn't get appropriate resolution. Mechanic claimed that there are some issues with the compressor of B3 berth and it will take time. We reached to our destination, however it wasn't solved.
We travelled in 3rd tier AC berth which was worst than sleeper, as there was no ventilation due to fix window.

We paid approx 1, 500 per seat for AC, which was't provided. Could you please assist how can I claim my money back? I trust Indian Railways, however can't spent my money purposely without any services, paid in advance.

Anticipating your response.