Default [Q] my gtp7500 issues

please i tried making my samsung gt p7500 into a calling device but i downloaded the modem and the enable call zip files, i did the normal pressing the power button and lower volume button just to push it into recovery mode but i dont seem to see anything in my sdcard, anytime i click update from sdcard i see nothing...i may not get the steps carefully......but PLEASE I NEED WAY TO MAKE DIS WORK.. i need a replyASAP! !!!