VODAFONE not giving satisfactory internet speed as per 3G connection promises

VODAFONE not giving me the internet mobile brodband speed through dongle of 3G network as per the name of 3G and speed written on the dongle pack.
a download which was taking 1 day for download on 3G its ironical to say is taking 5 days for download. costumer helpline not giving a suitable assistance.
contact number : 8585992910.