Hi, sorry for the late reply. You can find a file called 'SaveData.json' at this path 'C:\Users\yourusername\AppData\LocalLow\PinkTea\Realms Of Bondage'.
If the size of the flie is 0KB, you can just delete it and the black screen problem could be fixed I think. If not 0KB, can you send a copy of it to me before deleting it?