This happens to use all. When we have FT place, PT people respond. When we have PT place, people needing FT respond.

Our hours, location, curriculum, fees, will appeal to some, not others, so we all just have limited pool of potential client. All you can do is sit tight, be grateful it not common occurrence and trust some will show up eventually.

I think it too much to ask for deposit and also first month of care! Few can afford that. I not think that's very common. Most ask for deposit, and some ask for full month pay in advance of service, but not in advance of start date.

If your policy is to charge both, why did you not address when you saw only deposit paid? And I think the fact you cashed deposit, is sign that you okay with it.

I understand you want some guarantee but is that not what she gave you with deposit? And if you really have multiple people needing care, then why are you worried about empty places? I not understand. She will likely be concerned about giving a whole month fees as well as deposit as that's a lot to hand over. She has to trust you to be ready for her child on start date but I think you also have to trust she is really coming. She's invested deposit as a sign of her investment.

Any help with dealing with parent about payment super early because i have no money or is it to much and i should expect her to pay the first day of care?
It might sound harsh but she is not responsible for your financial situation. IT is too much to expect so much esp as she likely on mat leave and so limited income. I think as you had deposit and cashed it, then she shouldn't pay more until first day of care.

And what can i do to be more secure financially when childcare contract ends and you find replacements.
There are risk with self-employment and times of low income are part of it. You have to save some money when full for times you might not be. I not hold places which empty for long time as too much lost income. It risk to turn away someone wanting care in 6 months (or however far in future) but that decision you made.