Unable to enable me making international calls

I am a Cell C customer for 15 years. 2 weeks ago I noticed that I couldn't do international calls anymore. I went to a Cell C branch in Cape Town Claremont. The service consultant checked all my settings in their IT systems and mentioned that I should be able to call international numbers and he doesn't understand why I can't. He asked me to restart my phone which I did twice at the branch without any change. Then he assured me to log a query and that I will be called by a technical department. After 2 days waiting without being called I phoned the Cell C customer service centre only to figure out that they couldn't find any query. Now the lady submitted a query and I got confirmation by sms including a reference number. After 3 working days I didn't receive any response and I phoned again customer service centre. The lady checked the query and put me on hold for 5 minutes. Then she informed me that she spoke to her colleague of the technical department and I would receive a call anytime from after we finished the call. After more than 1 working day without any response I phoned again the customer service centre. I gave the lady the query number and she couldn't find it. She put me on hold to talk to her manager. Then she informed me that she will ensure that I will receive a call from the technical department first at the very next morning. Additionally she submitted another query with a new reference number that I won't be forgotten. More than 1 working day later I still didn't get any response. So I sit now with my problem almost 2 weeks without any solution.