I’m not sure if it’s the education system, or the specific customer service training that people get, but this YouTube video highlights how ANY information you receive from a customer service representative over the phone is suspect.
The issue is not that the customer service people didn’t have the information to hand (some obviously didn’t), but that even with the correct information, they didn’t know how to communicate it correctly to the customer.
Rhonda Bracey: At Random 
Strangely enough that makes me feel much better about my head-bangingly confusing experiences with three.com.au. When three customer service people contradict each other it’s possibly not my little brain at fault.