you do two things to make it work
1)edit the script and make it give rewards directly instead of updating sql with query_sql
2)make an item which can be usable/ tradble with npc for cash points
3000,Gcoin,Credit Coin,0,5000,,40,,,,,0xFFFFFFFF,7,2,,,,,,{ set #CASHPOINTS,#CASHPOINTS+500;specialeffect2 590; dispbottom "You got 500CP, now"+strcharinfo(0)+" have "+#CASHPOINTS+" Cashpoints in Total";},{},{}
this db code is for usable cash coin/
edit your lua file as you need