Molds definitely can and should be used more than once. If it's a candy mold, it may break after 15 or so uses but if it's a regular soap mold, with tender loving care, you will literally get hundreds of uses out of it.
The soap is sticky and tacky when it first comes out of the molds. This is because of high glycerin content in melt and pour soap. You'll notice that tackiness going away after as little as one hour. Was it a Bramble Berry base? If so, which one? Various bases act differently in molds and at pop out. If the soap was difficult to pop out, you could do the fridge/freezer thing but you'll also want to examine how long the soap is in the mold to start with. I usually let my soap sit in the mold for 4 hours before trying to gently break the air lock by prying the molds away from the sides of the soap gently.
Yellow food coloring, while lovely in soap, is not all natural. You might consider a yellow oxide like the liquid yellow oxide here:
http://www.brambleberry.com/micas.aspx#liquid Or you could use Saffron or Annatto Seed that has been infused in oil for an all natural yellow.
Once you get the general feel of how melt and pour works, you're going to love it. It's completely addicting! =)