I received my BT sim through the post a few days ago, and started using it straight away, everything working fine (mobile data, calls, texts). I then decided to transfer my old number to my BT contract, to avoid having to contact people with a new number. This all worked fine, however my phone will not connect to mobile data, and shows no 4G, H+, 3G or other notifications when I turn on mobile data. I've tried everything I can think of (APN, switching to the correct service providers, and even tried a factory reset- lost all data and had to start again) and it still doesn't seem to be working. All I can think of is that because I've used the mobile data on the old number there's been a problem activating it on the new number. Any help would be appreciated.
Further to the above [good] advice, is there another mobile you can try your sim card in?
Also does another sim card in your phone allow your mobile to use data?
Edit: If you ionstall the android app 'Network Signal Information' by Kaibits on your phone, you will be able to detect whether there is actually a data signal [and what type of data] is in your vicinity. [If you are an i phone user, I'm sure there will be a similar app at your disposal].