Sorry about not replying to your original ticket - I've just sent you a reply to your new ticket, with some information about your current predicament.

As for the purchase limit - there are some speed limits set on our payment processor's end, but on our end we're only limiting gifting. These were not the cause of your payment problems, which we are investigating to the best of our ability.
Unfortunately we haven't been able to recreate the problem yet, as it appears to be randomly occurring. Clearing your cache and cookies - as well as making sure that you aren't running any software that might be modifying the cookie files - might help. I apologize for any inconvenience caused.