Full signal and 4g but not working

​@Jake Sheffield  Even that you have been getting these signal reading there are many factors why some people get faster or slower even non-responsive network activity. 

Try putting you phone into Airplane mode for 2 minutes and turn off airplane mode and try using the phone normally. 

Just to add have you check if there had been any reported network issues in your postal area this may also be a possibility to you ongoing problems. 

https://www.idmobile.co.uk/help-and-advice/coverage

Also you may want to try factory reset of your phones network settings as outline below. 

iD Mobile Specific Information:

• If you're having trouble with your iD Mobile data, you can try resetting your phone's network settings: 
  • Go to Settings. 
  • Go to Carrier. 
  • Tap Automatic to disable it. 
  • Tap any network that is not iD. 
  • Wait for network selection to fail. 
  • Update network search from manual to automatic. 
  • Your network selection should be done and your data connection should be reset.
  •  

Joe