Often when you bring up an issue – even if you say it with sensitivity and with “I statements” and all – the other person may want to avoid dealing with the issue. Stay focused, don’t fall for their distractions.

Some typical distractions are:
Denial: “I would never do that.”
Defensiveness: “You weren’t there, so you don’t know exactly what happened.”
Deflection: “I’m not the only one who does that. Why are you bringing it up only to me?”
(Note that these are all ego-protecting mechanisms.)

Bring the conversation back to the issue at hand. “I want to focus on [the issue I brought up] so we can resolve it.”