BSNL Gprs — MY BSNL POSTPAID GPRS NOT WORKING

My gprs is not working, in my htc 3452 handset i tried other bsnl card, where in gprs was working, i checked all setting needed for gprs, my seetings was also ok, when i made complain to bsnl office they suggested me to change simcard, but they r demanding 100 rs as price for simcard, sir my problem is that, as gprs is not working on my sim, so its technical problem, in case if sim is lost or damged by me then it become my problem in that case rs 100 charge is ok, but bsnl people is demanding rs 100 for simcard change, ( in my sim incoming and outgoing facility is still active, that also confirms that my sim is not damaged ), so bsnl should offer me free sim, or my sim should be changed free of cost,