"An error has occurred while trying to process your request. Please, try again"

@Hekkatoid 

support said that none of your attempts have been 24 hours apart.

They advise to wait 48 hours just to be on the safe side now, tho they can see you had issues before that as well so may not of been related to the earlier purchase issue.

maybe add that card to a paypal account and try purchasing via paypal is my recommendation