Does it get any attention between uses? If not, I think that's your problem. Composting is a continuous process....the drum has to be rotated to aerate the material...it has to be "fed" enzymes or bacteria on a schedule...the temperature has to stay well above 70 F, 'cuz bacteria become increasingly sluggish below 70...till they become totally dormant at 40. Bacterial activity is essential to composting.We installed an Envirolet composting toilet at our comp in West Virginia. It is only used about two days every six weeks.
So if you just use it for those two days and then just let it sit there for weeks, it's not gonna work...some kind of fan and heater has to run continuously and rotate the drum on a schedule or somebody has to tend it at LEAST weekly...liquids have to drain as the material breaks down..new peat moss added and enzymes. A little homework into how to use and maintain a composter before you installed it could have saved you from an expensive mistake. For the kind of use it gets an incinerating toilet may have been a better choice. You might look into selling the composter and replacing it with an Incinolet - I N C I N O L E T -