Help with dealing with contractor

[Miguel Hernandez]

Hello fellow BP members. Hope everyone had a great Labor Day weekend.

I am from Los Angeles but I target homes in Wisconsin. Currently I am in the process of rehabbing my first BRRRR, but I've ran into an issue.
My contractor and I started off great. He gave a great bid, we discussed the rehab, rehab budget, and we both came up with a reasonable date for the work to be completed. However, during this rehab process, one of my units (the property is a duplex) had LOTS of mold in the kitchen. The mold was so bad, most of the walls had to come out in both units! The cabinets had mold in them as well. This added a couple more thousand to my rehab budget, which I was fine with because I gave myself some cushion. I know this issues will cause the rehab to take a bit longer, but now we are 1 month behind schedule. Our contract states that work should have been completed August 3rd. So I was trying to be understanding and nice, I called my contractor to get a new confirmation date, and he said he got on another job that will be taking him away for a little bit, but how can he take another job when my rehab is behind? I don’t want to create bad blood, but I’m also losing money because this rehab is taking FOREVER. It’s been almost 3 months. Can someone please help me, I am frustrated and want to blow up but I know that is not good business. How would you handle this situation? Thank you.