Contract
پوسٹڈ بايئ Frank (confidential) انرر جرمنی فورم
I am just telling you the legal side - you made a contract and agreed to the terms and conditions, now (legally) you must abide by it.
If they, out of goodwill (and to keep their reputation), offer you a better deal, that's up to them. You have a bad negotiating position, but maybe if you offer them half the amount, they'd take it. It is not realistic to expect them to settle for nothing!