I bought a 4 wheeler, and a few months later I decided to sell it because it was just sitting in my garage. My in-laws asked my hubby if they could take over payments, and I said only if they make the payment on time each month. (My mother in law doesn't stay on top of things and they are often late on things.)

They agreed, but 6 out of 10 payments have been made late and I tell my husband to let them know that it is becoming a problem because it is looking bad on my credit, but he won't. He says he doesn't want to start problems, but I am to the point to where I am going to take care of the problem. What should I say and do about this? They act like the late charge isen't a big deal, but it looks bad on me!
Additional Details
I told my husband that I really didn't want them to take over the payments but when he insisted, I told him to make sure all of the payments were not late. I forgot to add that above.