Selldirect punishing consumers for their mistakes

I upgraded to a P10lite through Selldirect. Two days after the device was delivered, a consultant contacted me to advise that they had delivered a P10 instead of a P10lite. The consultant arranged for the collection of the incorrect device and delivery of the correct device for the next day. When the courier contacted me the next day, he said that he did not have the correct device with him. He provided a contact number which I called. I spoke to two consultants who advised that I first have to return the incorrect device and then after 3 to 5 working days the correct device would be delivered. Bear in mind that this whole situation is as a result of Selldirect's incompetence, so why I should I be without a device for a week - no access to my messages, contacts etc. I further explained that the new simcard is smaller, and as such, I cannot even use the simcard in my old device in the interim. The consultant was still adamant that I have to wait for the new device. She even went so far as to say that if I do not return the device, I would be billed for a P10 which is more expensive. Really?? I agreed to pay for a P10lite, so why are you threatening me with a higher bill?? Also, if I return this device and wait for the correct device, I will still be billed for the whole period, even though I will not have my device for the whole period. Is this how Selldirect does business, by threatening and punishing their consumers (by me being forced to wait a week for my device) for their incompetence??