OK Lisa ........... that's fine. It's still a good make and model. I could suggest dismantling it and look for obvious bung-ups ........... if you're confident.
Also, you could ring Triton Technical Dept.. Most big shower names have a tech number.
http://www.tritonshow...er-sales-service.aspx
Maybe the cartridge is faulty. I've had an account with Screwfix for years. They're always quick to exchange anything faulty ........... no questions asked.
How long ago did you buy it?