Instead of going through the reimbursement process, my supervisor has raised a request for my night-shift allowance worth one-third of my salary in our company request system website.

I have never served in the nights.
They just want me to return those amounts once it gets credited in my account.
Basically, they are misusing me for their benefits.

He also added that they are making this move with me since I am the junior-most member in our team and that any requests can be raised/approved by him. Whereas, that's not the case with my other team members, that would go to senior officials. At least those were his words, which is not true. He is the immediate supervisor for my collegues as well and he gets to approve them.

He might have chosen me because I am only 22 and inexperienced. He wants to use my naiveity. I can't give a polite e-mail as it might be monitored by HR. At the same time, it is difficult to talk to him in person as he is very persuasive and hardly smiles.

I want him to withdraw the request as I can't cancel it, I guess. I don't want to feel guilty for something which I have nothing to do with. Even though, he really toils for the company and my strong feeling that he isn't trying to deceive the company.

How to tackle this situation?