Wow, that's incredibly rude. I've never experienced something like that outside of Canada before.
Like what are you even paying roaming for if they pull stuff like that? Is there any acknowledgement that some of us are actually abroad most of the time?
Telecoms routinely sell people services based on the assumption people won't use them. This gigabit link? The user isn't ever going to saturate it, right? They are pretty much immediately proven wrong and get angry because their infrastructure is over capacity.
That they can get away with this false advertising astounds me to this day.