Deceased estate: Nightmare to close contract

As an administrator of the estate of a CellC client I am utterly shocked at the service (or non service) received. The client passed away on 10 March 2022. CellC has been informed via in-store, telephonically and email together with all the required documentation. To date nothing has been done to close the contract. Bills are still being sent for each month although this person has been deceased for almost 3 months now. The department supposedly responsible is not contactable directly due to some form of company policy so everything must go through the call centre. 12 reference number later and still nothing has been done.