Why wouldn't Marriott use some formal communication channels to notify the customers about all these? Emails, mail, facebook and twitter? Posting things that weren't echoed by the customer services in the call center, instead, by somebody who self claimed as "company representative" in public forums. That is such a bad practice.
I can't imagine that after 2,3 years of preparation, the whole final merge is still a big mess. Misleading communication, chaotic call centers, crappy apps/websites, frustrated customers. This whole merger will be a lessons learnt to other big M&A, worst than that, it will be (or already be) a big joke to general public.