First of all, you should know that you can't get the money back. You can say that, you'd better bend the rules. Sir, due to my negligence, I overcharged you, 50 yuan. If it is convenient for you, you can pay me 50 yuan. It is not easy for me to do business. If I don't have time, forget it. Give me a good review.

This kind of thing is said because the interest he gives you is too low, especially when you meet a villain. Admit it.