The worst Service ever experienced

Called the Call Centre on Wednesday the 22nd February 2023 to follow up on a delivery of medication that my mum was told on Friday the 17th February 2023 would be delivered by Monday the 20th February 2023. I was cut-off 3 times, firstly by a Jennifer, then by another gentleman. I eventually got hold of a Zanele that had promised to get the Courier company to call me. When I expressed my frustration of being **** too, Zanele kept defending her colleagues saying that maybe my mum and I heard incorrectly what the other agents were saying. When I asked her how did she know what the other Call Centre Agents said, she said she didn't know as it was not logged on the system - so I asked why are you defending them then? and she couldn't answer - this was absolutely the worst service I have ever experienced from any company for that matter