Cambodia takes ten business days, not including the day you applied. If you applied on Jan 2nd (1st was a holiday), you should have your results by tomorrow.
Unfortunately, there is no process to disagree with them. Their decision is final, especially when it comes to errors imputed into the online application. It sounds like you made a mistake and did not enter correct information in one of the two spots they highlighted. Your nationality ad country of passport should match. For example, if from France, you would state you are a French national and France is the country of passport.