Never been on a training course for mobiles. As I started 5 days before Christmas I didn't have a 2 week training course so everything I've learnt has been while at work or through self teaching
And if you saw the amount you had to learn per network anyway you'd be amazed
Throw in having to know various sales laws, company policies, company procedures, spotting fake IDs, knowing how to use the computer systems etc. I know people that have worked there for 6-7 years and they still come across something new every day.
Personally, if a customer had walked in asking the same question I would have told them to phone CS, but as I said before I wanted to check.
I apologise for being mortal and not knowing absolutely everything about every single mobile network possible
You try the job sometime