First Reno, GC asking for progress payment that wasn't contracted

[Joshua Spivey]

So I'm working on my first BRRR property and have encountered my GC asking for a progress payment that wasn't contracted in. We agreed upon a 50/50 payment deal. I was originally told that this project would be done on August 7, after about 4-6 weeks of work. But with so many subcontractors ghosting my GC, becoming unreachable, and/or general issues within the renovation, we still aren't done. He's also not done things we agreed to (place a sealant over suspected asbestos tile flooring before LVP), or chagned plans without notifying me (Locations of mini-split heads to different ROOMS, rather than more central areas).

So today he asks me for a progress payment "so he can pay the other subcontractors and recover cost of additional materials he's incurred."

I paid him $26k back in JULY when the project began, and I'm slated to pay another $26k when the work is complete (about another week [more at this rate or speed]).

What should I do?