fall foul of sb/sth
fall (a)foul of (someone or something)
To become disliked or to come in conflict with someone or something due to one's actions, often resulting in further trouble or conflict. Since you're new here, be careful not to fall afoul of Bill—he'll keep you off of every case if he's mad at you. I fell foul of the committee, and now I'm not sure how to improve my reputation. Ted fell afoul of the law when he was still a kid, and he's been in and out of jail ever since.
fall (a)foul of someone or somethingand run (a)foul of someone or something
to get into a situation where one is opposed to someone or something; to get into trouble with someone or something. Dan fell afoul of the law at an early age. I hope that you will avoid falling afoul of the district manager. She can be a formidable enemy. I hope I don't run afoul of your sister. She doesn't like me.
fall foul ofcome into conflict with and be undermined by.
2004 Sunday Business Post Australia's biggest wine-maker, Foster's Group, is the latest company to fall foul of the wine surplus, which is set to continue for at least two years.