International Calls, how they work? Paid for a plan with 500min but in my account says that is only 100min.

Hello, thanks for answering, but until now I'm still waiting for a solution. And I also now have troubles trying to make an international call since every time that I tried to call to Colombia, I get a message that saying that my plan doesn't not have that option, but I already activated the International Calls in my account.. So I paid for and addon that I cannot use.