Call waiting settings in Network+ not phone?

[congusano]

Today I noticed that the settings for call waiting is under Network+ and not under phone.
Any guess as to why its not under the phone settings, where one would, I guess, assume it should be, along with caller id, voicemail, text reply, etc?

 

[Digital Moe]

I seem to have no call waiting settings at all and I only found this out while I was on a call and someone else was trying to call me. My phone seems to tell the caller they have dialled an incorrect number so I figured my call waiting wasn't switched on but I can't find the option anywhere on my phone.

 

[Digital Moe]

I have called T Mobile this morning and the have enabled call waiting at their end still don't have the option on my handset.