Voting Question: How do I dispute an invalid claim against a probate estate?

My fiance passed and I am executor. He wanted no funeral and his family took him and had a funeral for him against his wishes. Now they are suing the estate for the cost of the funeral. It was a completely private service with no publication in the newspaper. When I told them he wanted NO funeral they said it was for the Mother’s closure. How do I get out of paying this claim?
It’s not that easy. The claim can hold up the closing of the estate.