What it means by taking a company private is that the company is no longer listed in the KLSE stock exchange but it doesn't mean that the company does not have to satisfy its investors. Today, Maxis is still not wholely owned by one single individual/entity. Don't get the "private" thing wrong my friend.

Among other entities in Malaysia which is not listed (private) is also Celcom, Shell, etc but does that means that the company is not doing well ?

Maxis might be in trouble today for its inability to provide good customer support all these years. Customers loves the brand and their nice Maxis number but since they now have a choice ... they want to move away to someone else who provides better CS/pricing. Try applying the same principle to our automotive industry and you'll be able to imagine it.