MTN data and call management

[upup]

I don't know if the other companies work like this, but I got like 200 call minutes every month, but so many is mtn to mtn only. With people changing providers, you don't know which number is on which provider anymore, eg 083 can even be on vodacom. When I got the contract no one told me about these minute swopping thing.

Also I believe with data, they get devided with youtube, facebook etc.
Is this even legal.Why do they do it.