Device out of box failure

Hi there my grandmother purchaseda device at one of your Branches at Jabulani mall Soweto on the 30/11/2024 and the device gave issues and now she's been taken from pillar to post;because if the device had a factory fault from the manufacturer that was supposed to be picked up,now they are blaming the grand-daughter whom she purchased the device for that shes the one who damaged the device,she was sent to the technician at vodacom and the technician confirmed that her granddaughter is the one who damaged the phone by choosing the wrong software,how so cos she was setting a device and then now they are given excuses ,I would like this matter to be resolved with prompt because she paid for this phone and it has been sent to repairs twice,even now they are sending them back and forth and this might be out of box failure but they are refusing to exchange the device ,also the cellphone consultant advised that the person they purchased the device for tempered with resetting and to me that doesn't make sense,can the store follow the proper OBF process and give the customer what the paid for and in good condition This query we want it resolved before the end of this week.