MTNL not replacing instrument

Hello all,I have an MTNL provided landline caller id instrument which is not working properly.The handset jack on the instrument has become loose and causes lot of static. Also handsfree function has become erratic.Whenever I complain about 'instrument not working' the people at the exchange simply change the handset wire and give the instrument back to me which does not solve the problem.I have asked them for a new instrument but they have refused saying it is not available. But my neighbour recently opted for caller-id instrument and was given a new instrument without any fuss.How do I get some sense into these guys?FYI I had received caller id instrument for free when my monthly was more than Rs.1500/month but now it is less than 1000/ month. Could this be the reason they are not replacing the instrument?My exchange is Mumbai 2527Thanks

woah crazy guys.did you try going to the exchange yourself and meet with some superior guy? that worked for me once 🙂 try it, or else there is no other way i know of