I am using vodafone postpaid sim from last 2 years they never give me full details of the ussage of my whole month through the email and when my bill is genrated they give me almost 17 days to pay off my dues.
Customer service- whenever I called customer care they always help me out from my doubts and problems and I never wait 3 minutes for their response
Prepaid services are also very good for the middle class but calling rates are very high now a days
So I recommend to you use the network