Do Not Pursue This Matter Any Further Letter

Dear Miriam,

I received your email. Until now, I still have no clue what the fuss is about.
And I have no desire to know. Unless this will cost me money or my job which I doubt it would.
Please do not pursue this matter any further. It is a waste of both our time.

Thank you
Celia

None of your Business Letter

Dear Colleague,

Perhaps you should keep your mouth shut. I would prefer you rather not tell everyone about my private matters. This is none of your business.

Up Yours,

Co-Worker