Be/have nothing to do with somebody/something
Definition 1 of 2
Pro Tip 1/3Non-involvement
Use it to emphasize you or someone else's lack of connection with a person or event. 
Despite the rumors, I have nothing to do with the company's decision.
Pro Tip 2/3Disassociation
Expresses a strong desire to separate oneself from someone or something. 
She made it clear she wants nothing to do with the project anymore.
Pro Tip 3/3Denial of Responsibility
Asserts that you are not responsible for an action or situation. 
I have nothing to do with the mistakes in the report.