Closure of Cell C contract

Please note dates and times below regarding correspondence with Cell C and closure of a contract with no commitments ie contract could be cancelled anytime as it was way past it's 24 months.

21 Jan at 10h52 – I informed Cell C that the account holder, my sister had passed away on 5 January. I attached a copy of her death certificate as well as her ID 21 Jan at 10h59 – received an auto-reply with a case number informing me there’s a turnaround time of 48 hours 21 Jan at 11h22 – an email from Cell C to Vodacom requesting them to assist (with NO explanation to me where my sister’s account is lying – Vodacom or Cell C yet who am i to know the finer details) 17 March – I did a walk in at Cell C Kenilworth Centre looking for assistance, this matter was escalated by them 24 March – I went to Cell C Kenilworth Centre and branch had still not received a response from Cell C

I want them to refund her money but was told by the branch it is not possible as her bank account has been closed. I am her Executor of her Estate and I demand the refund