So i bought a WIFI dongle of Reliance for myself. And now i am getting notifications instantly on my phone. So it's safe to conclude there is a Problem with MTNL servers and not my mobile. I use the dongle most of the time now. Only for heavy downloads , i switch back again to MTNL wifi. So issue is resolved for me for now, but i hope someone finds a resolution for this and let me know here. Would be appreciated! Any suggestions?