JUST SAY , "I FORGOT"

Being unnecessarily suspicious and defensive takes a lot of energy. After a while you won't have to worry about whether or not people are trustworthy. THEY'LL just get tired of being regularly interrogated and constantly under surveillance, and stop dealing with YOU.
Making idle threats against people who know the truth only makes one appear guilty and pitiful. You can't get mad at folks when their actual, FACTUAL memory is working with as much, if not GREATER efficiency as your SELECTIVE memory. The presence of truth and proof makes being in denial, or sticking fiercely to a lie, that much more pathetic.
Say it's in the past. Say you forgot. Say you can't remember. Say there was a misunderstanding. Say you don't want to talk about it. Say you were IMPAIRED, even. But don't accuse someone of being mistaken or negligent. Don't call someone a liar or a traitor. Don't try to damage another person's credibility when your scheme fails, or your story won't hold water. Don't say it didn't occur, when it did. Don't say you didn't know, when you were actually notified. Don't say it wasn't said, when you heard it with your own two ears, or read it with your own two eyes.
Be honest--ESPECIALLY with things that aren't that big a deal. You don't have to go through the trouble of requesting that others charge it to your head OR your heart. If you forgot, Human Being, just SAY that!
One will never come out on top when attempting to cover one's mistakes by making another person look bad--no matter what the cause.