A lot depends on how much perlite you have mixed in with the c&s soil. It should be at least 50/50 and look like this -

Not using that much perlite is not the end of the world. But a big problem with commercial bagged C&S soil is that it often has too much peat in it. Peat can hold too much water and it can become hydrophobic and actually repel the water. So you might think you are watering the plant deeply and it is flowing through as you want it to do. In reality, it is flowing around the soil mix and not getting to the plant. I think that may be what is happening to your plant.

Since so many problems start with the roots, I would unpot the plant and see what is going on down there. And this would be a good time to remove all soil from the roots (this should always be done with a new plant) and give it new mix. Take pictures and try (again) to post the plant and roots for us.

If your roots and soil mix look good, we'll try plan B. ;-)