Premium Call Rates

[Saviour of iLectricity]

My wife does software support for an OEM controll and management system. The contractors installing and servicing these installations all have had training, have manuals and access to the software for installation and updating. They never take these things to site and mostly send untrained staff to site and rely and my wife to talk them through step by step when there is a problem. Some of these calls last 3 hours that are not billed.

I've searched far and wide and cannot find any information on VAS, premium rates calls. We just want to recover some of her time, also if the contractor knows that the call is costing them, they will stop sending palookas to site.

Any idea who to contact at a cellular service provider for information on this.