General contractor was hired for remodeling of bathrooms. Project with numerous delays and need to correct problems and mistakes. I have made all timely progress payments and even advanced paymemts per contractor request due to the delays and need for payment of materials. Now contractor is refusing to continue unless additional monies are paid. He is claiming additional work being done are order changes which requires additional payment, as the work is costing too much and he is in his own words "out of money". He is referring to changing shower valve/fixtures and associated plumbing/tile work as the newly installed shower fixtures were making water hammer noises and even resulted in water leakage. He had previously already agreed to make the changes and is halfway through that portion. He also installed grout over a portion of the tile being installed, but the grout was far too light and did not match the sample stick. His crew was informed and removed the grout but the contractor became furious about that. He never mentioned these additional work were order changes until now, and there are no written order changes for what he is contending. My contention is that these are simply corrective action for problem arising during the remodel. The contractor is now refusing to come work and also not responding to emails and texts. I would like to know how long I need to wait before claiming abandonment and so I can find alternative people to finish the remodel, and to also file complaint with CSLB. Thank you