Can't use data abroad

[Chris1566]

Landed in America yesterday and still can't get online without WiFi. Data roaming is on, spend cap set to unlimited and can't data roam. Tried adding a Rest of the World data pack and that won't work either. Weirdly it's listed in my add ons as costing £0 even though i agreed to pay for it, and it says 'resets on 6th January'. Can't see a logical reason to not be able to get online. Live chat unresponsive, twitter not helpful. 

[Chris1566]

Finally spoke to someone on live chat who said you need to manually select network as T-Mobile over here to be able to get online. Never seen this mentioned on any of the pages i was looking at so not sure how widely known that is. Also doesn't help given it's not an option as one of my providers when i try to manually do it. Basically a nightmare using Three abroad.