Inheritance and child support?

I pay child support to my ex wife for my two daughters that I have 50% of the time. I also pay all their day care expense, medical, dental, clothes, medicine (even cough syrup and Pedialyte) after school programs and everything that goes along with that. She doesn't pay for anything or even take them anywhere. She actually took her daughter from her first marriage and one of her friends to dinner and left my 11 and 3 year old home alone with no phone and told them to make a frozen pizza. She received a very large inheritance from her father in access of $400,000.00. My question is; Can I take her back to court and have my child support lowered in Michigan? Is it wrong of me to want to do this?
--------------------
Inheritance money IS income for child support purposes. You should file a petition for modification. The child support agency should pro-rate the inheritance over the number of years until the youngest child is 18 and add it to your ex wife's income. (15 years until the 3 year old is 18 would add $26,666 per year to her income)
Source