AFAIK the newer byond boxes are "loaned" to the customer so technically they can take them back if you stop subscribing. However normally they'll let you keep the box so that you can quickly re-subscribe to them in the future (and I guess give you the NJOI thingy in the meantime).

They almost certainly wouldn't take the wiring back (I think that belongs to the customer anyway so they have no right to). I also doubt they'd take the dish back either as it's more hassle than it is worth and discourages the customer from re-subscribing in the future.

Despite all that, if they tell you that you have to deliver the stb to them I'd tell them to f*** off and come and collect it from your house at a time that is convenient to you. Or tell them to send you a postage-paid box to post it to them.