Poor customer service and ineffective call centers

I have called the call center on the 10th of October 2020 for my Bill's to be split they promised to call me after 48 hours to complete the splitting process and they never called. I called again Wednesday 28 October 2020 till date I never recieved their call. I was on hold for over 15 minutes and the consultant still failed to solve the problem. I requested for the settlement amount for my accounts still they refused to give me but he insisted on escalating my problem. At first my accounts were split I don't know how they linked them without my consent.