You initially asked for 3 extra boxes, but only sent 2 - because this is all the system would allow on one order. You then called again to complain that one was missing, so the agent ordered another one - they shouldn't have done this, as 3 boxes in total is the maximum you can have on one account. This is why it's telling you that you have too many.
You can just acknowledge the message to transfer the subscription to the box you're currently using, but it'll remove it from one of the others each time. You won't be able to use all 4 boxes at the same time.
