to have told me no
Deberías haberme dicho que no sabes nadar.
You should have told me you don't know how to swim.
Deberían haberme dicho que no saben nadar.
They should have told me they don't know how to swim.
Debería haberme dicho que no le gustaba la ensalada.
She should have told me she didn't like salad.
— Chungking Express (1994)
Deberíais haberme dicho que no sabéis nadar.
You should have told me that you don't know how to swim.