Printout the online status,
Walk-in/appointment(infopass) for Stamp on Passport. Talk to officer explain them, here is why I am saying this.
If they found u r approved in their computer than
Atleast u would get PP Stmamped. and they would filled 181- creation of record for PR REg. and Card would be ordered... and the main important thing is to verify ur address there.
Here the thins work in this way, if they sent letter, which was not delivered to any reason, it is sent back to them and they keep in file untill u contact them(I believe).
so go for stamping and take all necessary doc with u. don't worry if they found u are approved, they would stamp.
thean u can send letter to service center about 'not received' ur approval notice if they find it was returned they would send u again, if their record showed it delivered than probably filling 824 would be reasonable option.
Good luck and congratulation on approval.... I know it painfull situation but feel urself lucky that u got approved.......... missing letter missing doc...... its headache but ....... may be there is some reason. God knows that
Good Luck