* It's a regional saying: Some phrases are specific to certain geographical locations or communities. If you heard it somewhere, it might be a local expression.
* It's a misspelling: There might be a similar phrase that is more common, and "Black Ban" is a misspelling. For example, "Black Ball" is a term used in some social clubs to indicate a rejection of a potential member.
* It's a misunderstanding: It's possible you heard something that was not a complete phrase, and your mind filled in the blanks incorrectly.
To help me understand what you're looking for, please provide more context:
* Where did you hear this phrase?
* What was the context of the conversation?
* What do you think it means?
With more information, I can help you figure out the origin of the saying or find a similar phrase that may be more familiar.