A few people seem to be reporting this.
I'd suggest contacting 48 support directly to see what they say:
You might be able to topup your cash credit balance by voucher and then buy stuff (membership/add-ons) online or by text in the meantime?
Hope this helps.
Same i cant buy membership either???
Sorry about this but we do have an issue with payments right now. We have the guys working hard towards getting this sorted. I’ll have an update for you soon. ~ Damian from 48
Im having the same problem when will it be up and running again
We have found the problem and have guys working on it right now.
You will notice the site has gone down while we work on the fix.
It won't take too much longer.