Looking for a suitable card plattform provider

I'm little of a newbee trying to start a voip business selling international calling cards. I want to start in the right end and are looking for me the best plattform. I've looked into IPsMarx, PEC Telecom and open source like Trixbox with FreeBX. My plan is to start in Sweden and then imply the technology in Northern Africa. I'm better in business than technique, so I'd be happy if I start in the right end.