Generally the box slows down after 1 day of use. You have to power off and on again to get it to work at normal speed. This is the case EVEN BEFORE the ticker which started running on all channel. Sometimes when you try to change channel fast using up/down button picture will go off (the info bar appears, but no picture). Then after 5-10 mins again the picture appear and it will reset to Ch 100 automatically. When this happens generally power off on will solve it for another day or so. However, this is something very new to Tata sky. Earlier the channel change times used to be very very fast (esp MPEG 2 box). Even with new MPEG 4 box, it was ok, but recently (2-3 months or so) it has started becoming laggy.
I don't think customer service can do anything. But our vigilant customer here can take this to the right level using their insistence with customer support. This seems to be a software issue, nothing to do with hardware/box.