loss of data loss of mind

I have a 3 gb topup contract. My data has always lasted for the entire month often leaving me with atleast 1gb of data. Recently I have experienced huge data drains even though my usage has not increased. I have checked my laptop for update settings etc. Can I please have an answer as to why is data being lost. I am not the only person experiencimg this data drain. I have 3 data contracts with you and experience the same challenge on all 3 . Please investigate especially my 3gb contract. If it can not be resolved I will have to move networks which i would not want to do freely as i have always received good service fom the network.