Urgent till Tuesday: Job contains interest

Salamu alaykum urahmatuLlahe ua barakatuhu,

I have a job interview on tuesday. The job is about giving subsidies to companies, univesities etc. for investing in their digitalization. The problem is, that if turns out that a client asked for too much money they actually needed, I have to reclaim it and charge interest starting at the time they received the money till they pay it back. Is this job halal or haram?

Thank you very much, barak Allahu feek!

Danial