Watch your credit card statement. Got a bogus charge. I had to find it myself and call to find out that there was a glitch in their system and that they were trying to determine who they over billed.
On the phone for an hour to find this out. Not impressed. It seems they will send you a message for your monthly top up but when something like this breach of trust occurs you get nothing from them. Be wary I know I will not be using automatic top up with my credit card any longer.