Isn't it still available, they just aren't running an instance for public use anymore but I thought you could run your own?
You can run Galactica (the "base" model) for free on Colab (https://colab.research.google.com/). It takes about 4 minutes to start up. Just specify a "GPU" runtime on colab, and follow the simple instructions from their github (https://github.com/paperswithcode/galai):
!pip install galai
import galai as gal
model = gal.load_model("base")
model.generate("Scaled dot product attention:\n\n\\[")