I received an order for Google Tag Manager setup Last week. While I was working, I saw my client's website had a problem, due to which I could not complete the order requirements. I told my client about this problem and I said "I can solve this problem, but you have to pay extra for this".
My client said to me, "I don't have enough hand cash right now. Can you please solve this problem now? I will pay on the 11th of next month."
Then I fixed it and delivered my ongoing order.
Now how to get that fee (extra) from him?