cheated customer care,excess of postpaid bill no 9830324172

Location/place: west bengal,bardhaman

Name of company/service: vodafone kolkata

hi,this is pulak mukherjee, a student,my vodafone no is 9830324172,my credit limit 500 rs,nd my plan is talk more 299+ promo 49+ internet pack 199+ internet pack 99,bt frm the 1st day of my bill circle it was 99 internet pack activated,after using almost 1 gb of pack,i asked customer care to acctivated 2 gb internet pack,thy did nt told me that ur previous pack would be for only 7 days,and for tht ur usage 204 mb consider your pack,nd other 800 mb charge as 10p/10kb,,now they tell me that,which means i have to pay 8000 rs to vodafone,they use innocence customer,nd cheating with customer,for a student lyk me,it is impossible to pay 8k.nd how they make that??..where my credit limit is only 500,how can it possible to make the billing amount 8k, and why not their customer care executive properly train before they posting that post?