How to handle owners who don't acknowledge problem dogs?

I am currently doing daycare for a two year old dog. I met with the owner and the dog at their house because I am picking him up and dropping him off each day. The meet and greet went fine, the dog is small and tried to hump my leg. I made a joke about it and the owner said he doesn't hump he is just holding on to my leg... obviously not the case but it wasn't a big deal at all.

When I brought the dog to my house first day everything was fine, got a long great with my dogs and had no accidents. Second day came and the dog marked in my house six times in 30 minutes. The dog is male and isn't fixed. I contacted the owner to let them know I was having issues and may not be able to keep him for the rest of the day care booking. The owner apologized and said he never pees at their house etc. I had to crate him most of the day because the moment I let him out he would go and pee on my furniture.

I am on day three and the dog again tried to mark so he had to spend most of the day outside and in the crate. This day he started humping my female dog and pinning her into a corner and making her cry because she was scared. I immediately took the dog home and put it in his crate and noticed there was dog pee on a lot of their stuff.

The owner wants me to continue the booking but I do not want to and am unsure of what to do. I feel the owner was aware of these problems and hid them from me. I tried discussing it with them and they are dismissive. It is at the point to were my dogs are upset now and that isn't fair to them. If you were in my situation would you cancel the rest of the booking or should I keep him crated and outside at my house?