Their ability to do automated recurring billing, amazingly, is also lacking. I really wish they would fix that already. It's kindof a deal breaker for most people.
I had an even more annoying issue with their billing system.
I had 5 VPSs and whenever it was time for renewal, one of the VPSs would turn off ~5 days prematurely (before the renewal date). I contacted support multiple times about the error in their billing system until I got too frustrated and migrated last month.