i brought an iphone 4 but its locked with an carrier who do i unlock it and check what carrier it is with?
brought it off someone but didnt tell me what carrier it was with
iPhone 4S
Call the seller and ask. We don't know who the cellular provider is. Look in the device's Settings for relevant information.
If it requires the Apple ID and password of the previous owner, and you don't have it and cannot get it, then the device is useless to you. Return it for a refund if you can.
Find My iPhone Activation Lock
In the future check first before buying second hand: How to check for Activation Lock before buying a used iPhone.
