Sky will not send an engineer out for a Sky Go issue.
You have said you have uninstalled it but did you do this which also removes files and folders the app uses:
Uninstall the Sky Go app and then go to 'C:\Users\[your user name]\AppData\Roaming (ensure hidden files/folders are visible) and delete the following folders:
Sky
Sky Go
And if it is present the Cisco and/or Synamedia folder in App\Data\LocalLow.
Empty your recycle bin.
Reboot your PC and then download and install the Sky Go app again.