Cell C
BIS fair usage data is 1GB received, Not 2GB

Why is my BIS data 1GB that i recieve each month, When the other people receive 2GB, Also SMS dont want to send it keeps saying short message transfer rejected. And i had 100sms left, And 500mb data, But when i checked today there is 0 sms left and 12mb of fair usage data. Please explain as we sighned up for unlimited BIS not a Capped service. Thank you