I sympathise. I dropped WorldSIM a couple of years ago and now use Truphone.com, who I found to be responsive when I had a problem. You can have your UK number transferred and can also have a US number, or Oz, if you want.
I do not use it for data, relying instead on hotels, lounges or service stations. Even McDonalds in Paris! For phone I find it very cost effective in Europe, USA and China / HK. A friend of mine in HK saved USD2,500 a year!
Hope this helps