charged for free data

Ref number ***. Logged a call as this month i did not receive my 1GB of data as i did for the last 23 months of my contract but charged full subscription. I've effectively paid subscription for 24 months but only received 23 months of data. I was charged for the data I used which would have been covered by my 1GB i normally get. Logged call a week ago and called to follow up. I've been told someone will contact me but nobody has called to provide feedback