Terrible service with an online upgrade

I did an upgrade online for a Samsung A6 on 12 December. Everything was agreed and approved. A few days later I got a message to say the phone was returned by the courier. I called in many times to rearrange delivery, but have been told each time by Sheralyn that they need to open the code and they will send the phone. Almost 6 weeks later I have not had joy and have not received the phone. The service is terrible, I honestly don't know why I am wasting my time. I should rather cancel the contract and move to another service provider.