Ann: Launch of Subsequent Direct Tender Offer by MSG, page-7

It sucks but you basically have to accept it. If you don't, you'll probably be stuck with private german shares that can't be traded.
I can't tell you what to do, but unless you think some day Marley Spoon will be an international conglomerate taking over the world, you need to accept this to ever see any money again. (This is not financial advice).