Pathetic service from the branch and Call centre

I have been billed for a sim card that I lost two months ago, I reported the matter to their call center and they said that I must go to their store, I did visit the store and I was firstly told that they are off line, I have been visiting them every week and each time I visit them they always come up with an excuse, I called their call center asking them to either send me a new sim card or pay me back my money and they declined to do so.