Do you want her not ?
if you want her then dance as she says.
if you are forced to divorce her because of her attitude and her relatives behavior, then take legal action.
im sure they will file dowry case on you, to blackmail. so if they have given any dowry then file dowry case on them, before they file same case on you. [ Ref : https://mynation.net/laws/bare-acts/dowry/dp.htm ]
and also ask you mother to file Domestic violence on her [ Ref : http://mynation.net/laws/bare-acts/pwdva/pwdva.htm ]