I just called (8:30 UK time Wed) to cancel for a refund which can't be done online even using the work around which was available a week or so ago. Results (I'm silver):
1. Called the gold number listed on here a few posts back. Got through fairly quickly but they wouldn't process me as I'm silver (fair enough).
2. Called the silver number. It told me to call the general number (0800 727 800) and hung up.
3. Called 0800 727 800. It gave out a message relating the difficulties and hung up.
Conclusion: it's not possible to cancel and get a refund at the moment unless you're Gold.