This is just a recommendation and not necessarily advice to solve your problem -- if your main interest is voice/video chats,
get Skype. The quality will be far superior to anything you can get from WLM and it usually just works.
You may also be interested in SkypeOut service, which allows you to call a telephone from your Skype. SkypeOut isn't free and the rates vary depending on the country you are calling, but are usually in line with cheap international calling cards, Jajah etc. -- about as low as you can get.