If you have an issue with leaving the UK, you should contact your airline or ferry provider. If they are unable to deal with your request, you should call UK Visa's and Immigration on.
0300 123 2241.
If you have an issue not concerning the UK government, you can go back to the home page by clicking continue and choose a different option. If you have, you can go to https://GOV.UK on your mobile devices for help and support.