You may not need to contact customer services... If you have access to part of the Europe map, then you SHOULD be entitled to the whole of Europe, it's just it now gets split up into smaller chunks to fit on your XXL, and it looks like you've somehow selected the wrong one during the update.
So try this first....
Connect the unit to your PC and run "Home".
Go to "Manage my XXL" (second menu screen)
Stay on the first tab "Items on my device" and click on the "+" sign next to "Maps"
Under "Maps" you should now see something like this (but with the Europe - Southern Zone mentioned)
Click on "Change Map Zone" and you should see this screen, where you can change to the "Western" zone which includes the UK:
Note it says at the bottom that you can change zones at any time (but you obviously need access to a PC and if you haven't previously downloaded the zones you want, you will also need an internet connection.
To see which countries are included in each zone (there is quite a lot of overlap), see the box in Home which is just to the right of my second screenshot.