Shocking Service!!!!!

Hi Have had my International Calls cut off and have been told that it is due to me having per minute billing, I have had the same contact for the past 15 years and have never had an issue!!! I have made several calls and when after several attempts I finally get hold of a call center agent they give me the same excuse and cannot give a solution, I then request to speak to a manager in hope of getting a solution and I get cut off every time. I cannot deal with this level of service any longer and will be changing my contract to another supplier.