Complex sentence: Apparently Schumacher never did, and she was forced to go it alone, resulting in a manuscript submission that the publisher rejected as worthless, and not from the same person who had written "West with the Night".
Split into simpler sentences: Apparently Schumacher never did, and she was forced to go it alone. The publisher purportedly rejected her manuscript, saying that it was not from the same person who had written "West with the Night".