That's not wrongful in the legal sense. Read my signature, kiddo. If there isn't a specific law that says you can't be fired for that reason, it's not a wrongful term.
It might be unfair. It might be unjust. It might be based on incorrect information. It may be that they are "wrong" in the sense that she's not doing what they think she's doing. But it's not a wrongful (illegal) term because there isn't a law that says you can't be fired because your employer thinks you're getting a kickback when you aren't. It's legal to fire on suspicion of wrongdoing, even if the employer is incorrect.
I was pretty sure it was legal, unethical but legal. Wondering if she could sue for slander? They are also trying to get her to pay them $1300 ?? So I talked to hubby and decided I'm now gonna have a notebook at guest services where I keep track of what they are telling me to do. I knew Oregon was the at will state and could fire you with no reason. But I had to ask.