For corrections or questions about the calculators, write to hello@thewizardofodds.com.
Corrections to the maths are the most useful thing you can send. Every formula on this site is shown alongside its result, so if a figure is wrong it should be possible to point at the step where it goes wrong.
If you are looking for The Wizard of Odds — Michael Shackleford's casino mathematics site — this is not it and we cannot help with it. That site is at wizardofodds.com.