After the reselection, it is up to the MS to establish a new UL TBF in the target cell (it was in DL or UL TBF before).
The sequence goes like this:
UL : Channel Request
DL : Immediate Assignment
DL : USF is given to the MS
UL : RLC data blocks
In the description of your problem, you say
“1.) MS is not responding to Packet Uplink Assignment and Packet Uplink Ack/Nack.
2.) After this there are a series of Immediate Assignment in which the access cause is “Answer to Paging” but after that also services are not resumed.
3.) Service got resumed after refreshing the page or after re openning the site or start starting the download aagin (i.e. when MS is sending the EGPRS packet channel request) again.”
Why do you expect a PUAS in the target cell ? There is no PUAS after a reselection.