My first instinct is to say get it now before it's too late. If they really do have a base (made by... another artist than you'd wanted, which is another unprofessional matter entirely), then you should grab it now and force them to mail it to you as-is, with the horns (if those actually exist as well).

From there, you can get any number of much more reputable makers to clean/finish it up for you, or try it yourself, or whatever you feel best about. I wouldn't trust them to finish it.

Also, "wary to send payments"? Of COURSE commissioners are wary now! It's well-earned.