Bad service

Good day

I was wondering if you could help us to get out in the situation we are in On the 16th on November 2015 my dad bought a bed (Diablo base set and clean shield)for R6428 at OK on credit and the agreement was to pay in equal monthly installment of R482 for 24 months the first installment commenced on the 1st of January 2016 then he paid up until May 2016 then he went to get some loan at African bank then the loan automatically paid off his OK balance which was on the 10th June 2016 as this was part of their terms and conditions after paying he later received the message saying that his account is in arrears as he did not abide by the agreement meaning he paid before the recommended time so my father did not acknowledge that message as he knew that he has settled his debt, up until he died which was on the 20th July 2017 so I went there close his account then they said his account is in arrears so we have to pay first before they could close of which is impossible because if a person dies automatically his/her debts are written off so now they are saying they will come and collect that bed we bought as we can't settle my dad's account