ADSL Data being stollen / *****

My data keeps disappearing. I have been trying to get hold of support for over a week via various methods. I changed my logon details, passwords everything last night. I went to bed with 23 GB and SWITCHED OFF the router and this morning the 23GB was used. In last 2 weeks I have loaded 50GB - this is not my consumption and based on router being switched off last night categorically indicates that data is being used via another means. I am unable to work and this is causing me huge stress - I need someone from Telkom who knows what they are doing to contact me urgently and resolve and restore my 50GB