Not helping me unlock my phone when I had to roam in the US for more than a month even if I was paying my plan punctually even when abroad.
Charging outrageous rates for international roaming of $29 MXN (around 3 bucks) per minute while abroad.
Piling up charges of roaming of calls that I didn't even answered while roaming in the US to an amount of more than $2500 MXN (that's around 250 bucks) in a month.
Cutting my service because some random "executive" (a.k.a customer service representative) dropped the ball while activating one of their "unlimited calls" modules so that a bunch of long distance and roaming charges piled up again.
Leaving one of my lines dead for a week when I "canceled" to move to an easier on the pocket prepaid plan with Movistar itself.
Having that dreaded all Flash site of them.
The non-arriving bill, especially when they've erred and are over charging me.
The omnipresent "Network busy" when I have to place a death or life call.
The seemingly always shrinking coverage area.
I can go on and on, but I guess you get the point.
Turns out their engineers indeed do work and they've been probing UMTS/HSDPA service(PDF) here in Monterrey.Hope they'll get their act together and actually release some of that to the public at: