Hi,
we do not give advice about this (getting money back). We are only a website about the A-kasser and a (free) guide about Unemployment benefits.
We can not help you here...the only chance we see, if your A-kasse will not pay you back, is to make a complaint to the public Authority that delas with complaints over A-kasse.
You can find more information here:
The page is only available in danish, but you could try to call Styrelsen for Arbejdsmarked og Rekruttering, www.star.dk.