Some people have fixed this by signing out of the App Store/iTunes, restarting their device, and then signing back in. That hasn't worked for everyone.
Check the updates to see if the apps requiring an update are in your Purchases History. If they aren't in your Purchases History, you can delete the app, and download it using your Apple ID if desired. If the apps are in your Purchases History, contact iTunes Support.
Purchase History Review. https://support.apple.com/en-us/HT204088
If necessary, contact iTunes Support. Either use the form or scroll to the bottom of the page in the 2nd link. Follow through the screens to get a chat or telephone option.
iTunes Support https://support.apple.com/en-euro/itunes-contact
iTunes Support – world wide https://support.apple.com/choose-country-region/itunes