Bad client service

My suster tried to change her cell number on Yesplay . Monday they said 24-48 hours. By accedent i couldn't take Yesplay's call on Wednesday and since then she's still struggling and they just don't care at all. everytime they tell her is been escalated to relevant department. So how do you work with people like this?Yesplay This is From Elize Van Aswegen