Protection from evil doesn't stop spells being cast it merely supresses their effects for its duration.
So, assuming your GM rules the geas of 'do what I say' is a form of ongoing control, a protection from evil spell will suppress the geas for the few minutes it is up.

Mind blank provides protection but doesn't elaborate what that means. I would rule mind blank stops spells from working as they are being cast but merely supresses already active spells if it is cast after them.