I've got a guy who did the digging for septic tank, drainage and leveling out site which is on a bit of a hill. He was asked repeatedly for a full quote but never came up with one and started the work without giving it. He's been paid 12k and never itemises what he's charging for. Now he's looking for more money and seems to be wanting the charge a second time for things done ages back. How do I handle him? Any tips would be really gratefully received.