Hi David, sorry to hear that, I hope things go better from here on. When you look at the renditioner window,on the right side, you will see a light bulb. Select this and you will see various parameters you can adjust. Try varying the renditioner lighting effects from internal to external and you will also see a difference too. Renditioner uses an 'averaging' algorithm in all things lighting which takes a bit of getting used to but generally you can find enough adjustment under the light editing box I mentioned.
Stay well and ask all the questions you want. Have a great week David.