I had terrible experience with Gumroad (more info: https://news.ycombinator.com/item?id=13139000) and even pinged you on quora: https://qr.ae/TUrSmp No response what so ever. I still believe Gumroad provides one of arrogant customer support I ever received.
If you have 'startup' with so many unhappy customer - its expected to fail. https://gumroad.pissedconsumer.com/review.html Focus more on being open, transparent and being kind. Good luck!