Incomplete product

I registered two addresses delivery and post they delivered on post and no communication was done when I got my parcel it was incomplete I called to inform them they said I'd receive communication never did and called back they said its been processed I am still waiting for the delivery even received an sms today I called now they telling me I have to make an affidavit. Problem is why should I go through all the trouble to prove that I didn't receive what was due to me and I am paying for it. And if I decide to stop paying I'll end up being blacklisted all because home choice is delaying. I placed the order September