I honestly don't know if it's a case you could win. You'd have to present your case, and contract, to a lawyer. Do you have any lawyer friends??
BUT leaving a 7 mo to feed herself, laying down in a crib, while the provider is all the way outdoors talking with a client.....that alone is a huge issue.
I can see, from a provider's viewpoint, why they'd prefer a month's notice. There are many here who do have that in their policies. I have a 2 week notice. Personally, a month is a long time to pay for services you don't want to use due to neglect of your child. I would pull your dd out FIRST and worry about the money part of it after.
Have you discussed these concerns with your provider? Have you met the other caregiver? Can you check your state's referral list, for any mention of complaints towards this person? Are there other dcks there; do they sound happy, are they interacting? Kids aren't always 100% happy little sweethearts but usually, you can get a good sense of normalcy or 'something just feels off'.
If it were me, I'd pull your sweet helpless baby out and find other care, like now. Then I'd contact licensing, to get info and file a complaint, telling them your baby seems to be left alone for periods of time past what's acceptable(if you're positive that's going on). Then check with an attorney to see if you have a case. It sounds like this might become a she said/she said issue. Courts hear many disgruntled parent cases so it's hard to separate that from a true provider neglect case. You need facts, proof, and a clear understanding of your signed contract. Another thing, are you sure this person is licensed with the state, or legally unlicensed? That doesn't say it all but it certainly can help your case. Have you met any of the other parents or formed any kind of network with them?
As far as getting neighborhood cameras....I'm not sure that would work or be legal.
Good luck with your decision. It must be so scary and difficult finding child care, and with all the negative stories in the media, we never seem to hear the good things.