Mexican Postal Service
Regarding the Mexican Postal Service (Servicio Postal Mexicano), there is an open debate about its effectiveness. No self-respecting business that places much importance on the timely distribution of its correspondence would rely on it for anything other than mass-mailings. Nor do most of its private citizens.
Couriers in Mexico
Companies tend to have propios, in-house messengers, for the delivery of important correspondence and paperwork of any kind within the city limits. Invitations for important functions are also hand delivered, although usually by a specialized delivery company, for about 8 pesos per delivery. Remember that most require up to a week to make the delivery from the time that they receive the material from the sender. For intra-Mexico correspondence a local carrier, such as Estafeta, usually does the trick.
Finally, for international deliveries, any of the well-known international companies work well, especially in the "overnight" categories (DHL, FedEx, UPS). What we are saying is that if you really want to get mail to someone in Mexico, scan and email the docs, fax them or send local deliveries by a local courier, out of town mailins by one of the big three previously mentioned.
Personally, I have never even seen a Mexico Postal Official deliver anything to my house nor have I seen them out driving around on the streets. Also, as it pertains to important bills like cable/internet and electricity and water, those companies have there own reps/couriers deliver their bills to your mailbox. What does that tell you? And even then you may not get the bill until the day it is due, or even the day after, if even at all. My advice...... keep a copy of your account #'s on each of your utilities and pay them monthly or bi-monthly (electric and water) at the pay stations at the mall (Grand Plaza) or at your local OXXO. Or you can try to pay them on-line.....if you can figure it out.
Don't get me wrong....it is very easy to pay your bills. You just need to plan on doing so when you are at the mall or in town if you live on the beach. Word to the wise.