Uh-uh. This is the woman doing math (and women are better at math they say). HALF. Half is your starting point on this and you stick to it until they beg to fix the thing. And then, when they start hedging on not being able to fix it soon enough, they'll negotiate down to about 25% and you settle.
And you DON'T text and you DON'T email. You go to their office and you POUND on their FUCKING DOOR where...you guessed right...some woman is sitting there working. And then you know who will listen to you.