What's your PSU make and model (or part number)?
As far as what's got fried is the molex connector that powers the LED hub and PWM fan hub. The molex cable is specifically made for NZXT H440 cases since it has +12V and ground connector for PWM fan hub and +12V, +5V and ground connector for LED hub. And i'm not sure if you can buy it separately.
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As far as getting a replacement, log-in to NZXT site and submit a ticket. You'll need to provide invoice of your H440 case purchase before NZXT can send you replacement part.