How can I restrict data use on an iPhone? I need to know if there is an app for iPhone 5 that would control the data (or lock it down entirely)?
Also need to control who is called and what callers can be received.
The full information on use restrictions in iOS is here. It doesn't include the ability to restrict the use of phone calls or data, but you can restrict apps like Safari that use the data. Third-party apps are not permitted to modify fundamental iOS functionality like this.