"Update
I actually just checked your account and yes you are set up as a commercial account so this is why local calls are billed, if you are not a commercial customer please ring in and discuss with the customer care staff."

Thank you.  It's amazing that I can get my personal details on this public forum before I can get them from WorldXChange!  (Only just over a month since I first sent them an email about the charges.)  

When I signed up with Xnet for my ISP I accepted an offer of the "Commercial" rate table for code access calls from my Telecom phone after being told there really wasn't really any difference.  Obviously there is. 

Of course I have now asked WorldXChange to move me to residential rates.  That's a communication we could have had when I signed up for VFX if only it had been raised then.   And a communication we could have had last month when I asked XNet why I was being charged for local VFX calls.  Anyway, thank you for your explanation, I hope it's all sorted now.