My employer charges for per diem. But now they are suspending what they were paying us. And telling us they arnt paying for travel time.
As for you, if you have a written employment contract that entitles you to per diem and travel reimbursement, that contract cannot just be unilaterally breached. But if you are an at-will employee, as most people are, the employer can change the terms of your employment and compensation. If this is because of the COVID-19 situation, I imagine you are not incurring travel or per diem costs. Reason and flexibility needs to prevail during this temporary mess.
If the employer is still charging other parties for what otherwise would have been paid to you, that is between the two of them.