If student veterans are being overbilled, they should be making complaints to the VA.
Here's the link to the GI Bill Feedback System, for student veterans to make complaints
Currently there are 577 complaints and 334 are related to student financial services. If you suspect that student veterans are systematically being overbilled you need to contact the VA OIG.
The GI Bill complaints are posted here:
Here's the VA-OIG hotline