This news report states that Malaysian Airlines does receive ACARS data from its Boeing jets, but that it declined to have these data shared with Boeing. Further, it cites Malaysian Airlines as stating that it received no ACARS data from the missing jet.
Malaysian Air Said to Opt Out of Boeing Plan to Share Jets? Data - Yahoo Finance
Of course the problem with this whole situation is that other than for knowing that the jet has not landed at any major airport, we are sure of absolutely nothing else about this flight. So much has been stated and retracted, nothing can be relied upon.