How Do Additional Revisions Work, Exactly? And How Can I Decline An Order?

[frettes]

For context, I have a customer who placed a 3-day order. I sent multiple sketches of the design for the project in the first day right after they placed the order. They went offline and the order was running out of time so I continued, chose a design, add a color, rendered it and delivered. Half a day after the due date, they went online and ask for a revision, so I did. I delivered it again and just before the 3-day automatic accept, they went online and ask for another revision. 

I only have 1 revision set in that order and additional fee for more revision. How can they ask for more revision without paying the additional fee? How does additional revision work, exactly?

Also, I can't do this 3-day replies from this customer. The order is a 3-day work. I could do it in less than a day but I set it 3 days because of time differences I've experienced with customers before. I know they're busy but 3 days for a single reply is too much (The order became a 9-day order now). They placed the order without contacting me first, if they're gonna place another one, I'm hoping to decline it. But I do not know how. 😥

This is a $25-dollar order. This could be finished in the very first day. I can't keep doing this. Any advice?