Hello,
I've the same problem, I cancelled my monthly subscription to switch plan, and when I did tried to pay my new subscription with the same visa card I used before, I got blocked. I also tried to pay with paypal and with verotel, none of these worked. I even tried with another visa card from another bank, same deal.
I thought it would maybe be a problem on SLR server side specific to my account, like if I was considered still subscribed for example, so I tried on another account just to be sure, same problem.
Is it a epoch/verotel problem or is it possible that there is some trouble on your subscription service for new subscriptions ?