Andrew, have you had any luck getting in touch with them yet? (Or anyone else with this problem?)
I'm trying to cancel my subscription right now and am having the same problem.
In the past when I tried to contact them via the support email address, the first time I got no reply, the second time I got a reply from the personal email address of the guy who I think is or was in charge. After that I contacted him several times and got replies immediately. Once when I asked to upgrade my subscription for the next month (there's no option yet on the site) and he wasn't able to get it done in time, he gave me 40 free credits. I actually cancelled my subscription with Emusic in favour of ALB because I found ALB's customer service so much better.
Now I can't get a reply from either the support email or his personal address. I guess I am just going to have to do the same thing and get my bank to block payment. This is really appalling.