Don’t worry about it. I had the same thing, I requested to return the device within 14 days, but I was able to use the Fairphone 4 for 1,5 months because support was a bit slow. They have some delays at support, but they weren’t that difficult about it.
I was also able to “send back” the accessories that were delivered weeks before I received the Fairphone 4. I quote “send back”, because I actually got a reimbursed the cost of the accessories, but I didn’t have to send it back. They said that the CO2 emissions were not worth it. Quite unique way of looking at it.
What’s the reason for returning the Fairphone 4? Some issues will be fixed soon with updates, there are also some workarounds. You may check this thread for some details.