Apple One Billing Problem

I am a big fan of Apple One but one family member keeps getting billed for additional iCloud storage. We have 2 Terabytes and use only a small portion. I have written Apple three times about this problem. They suggested that I have my family member check her subscriptions and she has done that and does not have a subscription on her phone. I've got a screen shot of that page in her phone. But Apple so far has been unresponsive. And we keep getting billed for the extra storage. How can I get this fixed?