Hi, Bramirour. No, they are not deleted at all.
If you look to the bottom of the Suggestion forum window you'll see there's a little section called "Thread Display Options".
In that section there's an option of "Show threads from the...", you'll find that is set to only show threads from the last year; change it to higher value and click the "Show Threads" button on the right to see earlier threads.
[center][url=http://forums.lotro.com/showthread.php?18699-How-to-get-help-on-the-Tech-Forums-and-how-to-contact-Turbine][color=gold]How to get help on the Tech Forums and how to contact Turbine[/color][/url]
[color=green]Please reply to the topic or PM me if a solution I posted works for you: The more data I can gather the better I can help.[/color][/center]