Entirely untrue. I had a rep arguing this with me about prepaid some time ago right here. It must have something to do with their compensation. Also, I'm not sure if it's available in store, hence the reason they wouldn't push it.

I've dealt with a lot of wireless reps in my day. It's my opinion that T-Mobile has some of the least educated bunch. A lot of that may be due to poor training. That said, I had a Sprint rep try to tell me that Metro doesn't use LTE for their 4G or their own towers. Yikes!

Your best bet is to educate yourself.