First, go to the travel agency and explain the situation to each other. You can show the other party the consumption record (bill) to prove this consumption.

Under normal circumstances, the other party can refund the overpaid money to you after verification and confirmation at this time. At most, the other party needs to confirm and sign with the superior leader after confirmation. (Most businesses will do this after confirmation.)

Then, if the other party refuses to pay the bill, you can call the police. After explaining the situation to the police, the police will be responsible for recovering the overpaid money for you.