"We've started by doing user interviews about the offending feature to see if we can better understand what it is about their interaction that may be deterring

"We've started by doing user interviews about the offending feature to see if we can better understand what it is about their interaction that may be deterring them from purchasing." This. Something sounds fishy. You should collect more data and interview more users. Are you asking the right questions? If you can't find anything about the "offending feature" that is driving people away from sales, then there might be some other hidden issue.