get (hold of) the wrong end of the stick

/ɡɛt hˈəʊld ɒv ðə ɹˈɒŋ ˈɛnd ɒvðə stˈɪk/

/ɡɛt hˈoʊld ʌv ðə ɹˈɔŋ ˈɛnd ʌvðə stˈɪk/

to get (hold of) the wrong end of the stick

to fail to understand or interpret or understand something correctly

Examples

1. You keep getting the wrong end of the stick, Tom.

2. You can see how I got hold of the wrong end of the stick?

3. I think you've got the wrong end of the stick here -

4. But it seems he's got the wrong end of the stick.