Contractor Won't Bill Me. Advice Please!

[Alecia Loveless]

I've got a great general contractor. In the past 8 months he's worked at 3 of my properties. The first doing odds and ends getting it ready to be sold, maybe about $3000 worth. Then he did a major renovation to the second side of the duplex I live in including installing a shower, laying flooring, and supervising other employees such as the plumber and electrician. This could easily have been as much as a $12-15,000 bill from him. He promised at my insistence I would be invoiced before December 31,2020 so I could properly account for these bills in the correct year. Now he is renovating a third house for me, another $12-15000 project. 

I have yet to receive a single invoice of any kind from him. I have referred him much business and many new accounts but I can't imagine he doesn't want or need this money. There aren't any other reliable, insured contractors in my area that won't simply charge me an arm and a leg for this type of work. He also comes at every emergency I have so I don't want to alienate him or offend him especially as my portfolio grows. 

If anyone has any suggestions on how I should handle this I would appreciate it. 

Thanks!