Hello VitoCorral, agree with the comments above. If you can change the soil, and add either pumice/perlite/little lava rocks, just to aid in drainage. I do have preference for pumice though in my media.
These are two of my ZZ plants, I made the soil as gritty/coarse as I can do it and it is happy like that, roots of this plant are fat and ably holds water so you have to make the media very well draining. I put those big rocks, to help me gauge if soil is still wet. Growing it indoors, dry out time takes longer, so when I lift any of those rocks and it still shows damp, then I delay watering.
This was my plant before, had to separate them into three, it was fun doing the repot last Apr2014, really made me understand why it wants to be kept on the dry side with those fatso roots:
