That is good. at least you know that they are interestingly working on your application. Have you by any chance resided at multiple addresses since you were 18 within India or abroad ?? ( which could make them think what your recent address is)
you are also approaching your 6 months time period ( after your approval) which seems to be quite a long time. You can call them on the number they have provided you or make a CSE and Email them about the status of your application.
Btwn you could have asked them on the phone about what is going on with your application. It was a platinum chance. But as you said, they did not give you a chance to ask any question. So get ready to attack them , the next time they give you a call.