The major problem I see with these barrel composters is that the material is just too wet to properly digest. Does yours have a putrid odor? You might find some help at the link below.

Here is a link that might be useful: Composting Tutorial

There is nothing wrong with compost tumblers. They are wonderful. You simply need to have the right kinds and amounts of materials.

Grass clippings and leaves work really well but you might not have many leaves at this time so you could substitute some horse bedding or shredded newspaper.

Pine straw is very slow to compost so not the best choice when you want speedy results. Also keep in mind that shredded material is what you need when you want that two or three week batch of compost.

Don't give up or let some knuckle head tell you that tumblers aren't any good. Keep experimenting. It's fun!

One thing that the manufacturers don't tell you is that your compost may need to sit and "cure" for a few more weeks after it cools off and before you use it. I have a couple old laundry hampers next to my tumbler that I use for this purpose. I'd say your two choices are either to add more fresh materials and re-start (re-heat) this batch, or else dump the stuff out to "cure" and start a fresh batch in the tumbler.

One bit of advice that I forgot to include earlier is that it's a good practice to have most if not all the material in place before you load the tumbler. You can still add a bit later but you really need to load it all at once to have the volume required to start the "fireworks"

It took my three tries before my tumbler heated up. The mix has to be right, the particle size small, moisture in the right range. When everything is correct, the mix heated to 160 or 165F in two or three days, the same as my mesh bins that I use now.

Over a few years I found the mesh bins to be much less work, so I have two large ones now. The center bar of the tumbler rusted thru after four years; but I had already quit using it.