Straight Talk 90% of international numbers not covered by plan, even though country is covered Internet

 I bought an International Service Plan from Straight Talk today, especially after  I read that there is a Refund Policy in existance. After activating the Service (which by the way didn't work with the provided SIM card), I tried to call an international number to a country which was covered by the plan, but it didn't work. The Service hotline then explained to me that I needed to call another number first which then would walk me through dialing to the international extension, which I wouldn't call a service plan. I tried that but had to find out that most of the numbers I called aren't covered, even though they are normal landlines which worked perfectly with the T-Mobile international plan. After requesting the mentioned refund because the service isn't usable for me, I was told that the refund only works with phones and not for services.