If you are paying a premium for a room temperature kit, you should be aware that the Kodak RA-RT developer replenisher functions at 68F (20C) just fine. So, no need to pay a premium.

You should also be aware that there are reports here on APUG that Fuji CA papers do not fare as well at RT. IDK personally if this is true.

And, if your paper is black, even in the borders, then it was somehow fogged. If the picture area is black and the borders are white or orangish, then this means that the paper was severely overexposed.