Overnight delivery takes 7 days or more

I made an OVERNIGHT delivery order on 7th April to Durban, and it was picked up on the next day, 8th April. After that, until now, the 14th of April has not been delivered yet. I contacted them through a chat tool and asked about EAT but no answer. And then, I suggested coming to their hub center to pick it up, then no answer either. I requested to respond to me 10 times, but no response.