Olaf from Coinbase here.
Sorry for the trouble with the cancelled transaction! We use machine learning algorithms to determine risk, and sometimes normal users are falsely flagged. Email support [at] coinbase.com and I'll review your account.
Thanks. I actually emailed that 5 days ago and finally got a response last night saying "... we have received your request and are working on responding to you as soon as possible ...." I like what you guys are building and hope to use your merchant tools, but I'm wondering if you are also going to hire more customer support soon? I'm trying to be as patient as possible, and I'm sure you're receiving 100's of emails, but the slow response time is definitely frustrating.