Please, please, please... train your receptionist, when they answer the phone, to say "Hello, this is Hotel/Restaurant X, My name is Y, How may I help you?" or something similar that at least announces where or what you are.
There is nothing more frustrating to me as a guidebook writer (or customer) who often calls businesses, to spend several minutes on the phone just trying to figure out whether I have called the right number or not, while your receptionist grunts, groans and mumbles inaudibly.
Please, don't let your staff get away with just saying "hello" or grunt like most do when they answer your phone. And further, put your BEST english speaker on your phones. But if you don't employ someone who can speak English, at least find someone who can speak Vietnamese clearly. Lets put our best foot forward and show some professionalism for our international guests.
This is not an isolated problem--most hotels and restaurants in Vietnam suffer this problem, and Mui Ne is no different.