Handing over a dead person

We received a call from VVM stating we owe money in August 2020. The person they handed over passed away in 2018 which we then went to Vodacom branch to cancel and handed in a death certificate. I sent a death certificate no reply I emailed and phoned and nothing. I got the same mail with the amount owing again today and when I called explaining the conultant was rude! This is pathetic and I will be going to see attorneys as this is harrasment they have no communication skills and no respect!!!!