Check Is In The Mail Meaning

(idiomatic) A common excuse used by debtors to put off creditors

Example:   Your check is in the mail. I gave it to my son to mail yesterday. I hope he remembered.
1989, Ceramics Monthly, page 77:
  The reply was usually either a story about financial problems, or the "check is in the mail" dodge.
1992, Donald L. Barlett; James B. Steele, America: What Went Wrong?, page 155:
  It was the sure-fire sign of a business— or an individual— in financial distress: The old check-is-in-the-mail ploy.
1997, Jeff Davidson, The Complete Idiot's Guide to Assertiveness, page 306:
  The person with whom you speak may be well schooled in the "check is in the mail" run-around.