I changed my name from KarlR14 to Sereaphim.
After i did this and start the game “legacy-of-heroes” he no longer find my account
In then end I must start from level 1 again with 0 cards.
Was this a name change after linking your facebook account? MMO accounts are linked to kongregate names so the game assumes a new name is a new account. You can get in touch with the developer and tell them your situation and they may be able to transfer the accounts across.
Contact the developer directly. On the game page, in the info box, you should see a “Report a bug” link that leads to a report. If you don’t receive a response within a reasonable timeframe (a few days), then click their name and send them a message from their profile.
Also, when did you post in the Legacy of Heroes forum? Was it with another account or was it on another website?