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My MIL asked to keep my daughter(4 yr) Saturday and Sunday. I said yes, packed her bag and sent her off.
Sunday night came and went and my daughter was not brought home. So Monday morning, I called MIL and she said my daughter was at her mother's(GMIL). Husband and I were not told she was going there. But MIL stated she would bring her that evening. It is now Tuesday 1 pm. My daughter is not home and I have not heard from MIL or GMIL. Now, I have a temper in situations like these. 
My first thought is to call the police and tell them my daughter is being held without my consent.
Anyone have a more rational approach?
P.s. MIL has no accountability. So a polite sit down won't work. 

I need the advice of women older than myself and ideally wiser.
I am the Dil and will try to concise my issue with my Mil.

Married 4 years. My mother in law and I have had the typical issues. She says we don't call or visit enough. I often perceive her advice as criticism. I can be brutally honest, she's passive aggressive. But misunderstandings arent too big. Typically she comes to me about a problem and I listen. If she says I've hurt her I apologize. Every time.

HERE is my problem: When I bring my concerns to her, she just gives passive aggressive excuses. For example she took my child to the emergency room for a cold. Since we live 15 minutes away, I asked that she discuss medical issues with us first unless its life or death. She responded that if I thought this was not normal then I must have simply married into a family that's more loving than my own.
Second example: My child has a peanut allergy. When I got to my mil house one day she was covered in hives. I told her she wasn't taking her allergy seriously enough. She said I'm just insecure about her being with my child.
Because talking to her has been so bad, I decided to write her an email. I told her about the lack of accountability. I cited examples of how I'd did something wrong and apologized to her. I then cited examples that me voicing a concern and her only diverting.

HER RESPONSE: I love you.

Yep that one sentence.
Now I feel patronized. Im trying to figure out why a person who refuses to respect me is worth my time. And id like insight into how to interact with her, if at all.

Side note: My husband is not close to his mother, always presents our unity. Outside of my phone calls and ideas to visit, she doesn't hear from him I do it because she tells the whole family I'm keeping them away. So I make the effort to keep my name clean.