Oh, it's Zero

I heard a radio commercial today for the Jitterbug cell phone, marketed as a simple, easy-to-use phone. One of the features they mention is the ability to "dial oh and be greeted by name by our operator". Um, okay, last time I checked the letter O was located on the number 6. So in the interest of keeping things simple, are they really telling people to dial 6 to get the operator? Or perhaps they actually mean ZERO? Saying "Oh" is not an acceptible substitute for zero, ESPECIALLY when talking about buttons that serve as BOTH numbers and letters!