You must try and handraise the kitten yourself. Where do you live? What can you get? kitten mothermilk replacement, goats milk? These two alternatives are the safest.
Exactly how to give food we will take later.
Does momma take care of the kitten otherwise? warming it up, washing, etc?
Is the kitten fully developed? hairy and decently round? Do you know how much does it weigh?
The next question, is if momma is done with delivering for sure?? Mommas not having any milk is rare...
Be sure you give momma good food, kitten type. Be sure she has calcium. Say this goats milk mentioned. Cheese, plain youghurt....
With a little luck her milk will come in, and also her maternal instinct will kick in...
Proceed to describe the exact situation, and we will guide you.
You can try putting the kitten up to her while stroking and praising her. Also try distracting her with tasty treats. And it could be that she is still in labor. It is important that the baby gets colostrum. Most feedstores sell colostrum, as do goat dairies and FFA & 4-H members; they often can direct you to a source of goat milk as well.