Well they say 24hrs, so i would guess that another phonecall may be in order.
Mind you, I can remember when I got a card for my sister in France, I left strict instructions with brother in law to leave the receiver on and not in standby. 2 days later I phoned them for a chat and as a matter of interest asked if the card was OK. Nothing's come through yet she said, "I keep switching it on to check, but they can't have sent the signal" :-bash
So I made the call again and it activated almost immediately, amazing what having the receiver switched on does for an activation.