Worst online order experience

This has been the worst online order experience ever, I am truly disappointed in the team handling this order. I ordered early April and now almost a month later I have received nothing and I am being charged interest for the purchase. In addition to this, I have been wasting my airtime daily to follow up and I am told that the supervisor will contact me and that never happens. What exactly must one do to get assistance and not continuously receive false promises that someone will get back to me. What is eve the point of the customer service?