Call Centre agents not willing to help

I bought R29 airtime and it just dissappeared so I called customer care to report the issue. I first spoke to Palesa who dropped the phone after I told her the story, I called again then spoke to Sindy Chauke who told me that they detect that I had sent 15 sms's to international numbers but I told her that I don't have any international contacts and my phone has been in my pocket ever since I bought the airtime. She then told me that it is not their problem, they cannot stop sms's from going off my phone. The numbers were traced and I was told that they are numbers from Rome. I have never sent sms's or made calls to international phones ever but Vodacom refused to help and told me that it is not their problem. This is unacceptable, I expect Vodacom to atleast assure me that this will never happen again and investigate the matter. Please train your call centre staff to better handle customer complaints or atleast pass the calls to their team leaders when they don't know what to do. I am very dissappointed.