Store denying paid items

My mom bought building material from Boxer Build in Centane in 2019, she had a debit order going off her bank account every month. When she finished making the payments she received a call from the store to say her material is ready for collection. Unfortunately when she received the call she was in Cape Town as she was gravely ill. Unfortunately she passed away while in hospital. As a family you can understand we needed to bury her in dignity. We made contact with the store as we are now ready to collect the material and it is after the grieving process. The store is denying us the material. We gave them a copy of the death certificate however the store is still denying us the material and they have no valid reason.

Please investigate this and possibly feedback to me. Wendi