The problem was likely due to cancellation requiring an email to support, rather than a way to do it on the site. That business was selling proxies to SEO people. I eventually let it whither because 1) I was not happy with my customer base's use of the product, and 2) chargebacks got out of control due to the above fact, combined with fraud. At one point it had a chargeback rate of 14%, and close to half of those were stolen credit cards. I'm now starting a VPN business, which will face many of the same problems, so I'm merely wondering the best way to mitigate this one particular reason for chargebacks.