Momentum's mess with my nephew's hospital stay

My little nephew has been in hospital for 7 months, since he was born. Every single WEEK there is a mess up with the medical bills which Momentum insists on trying to take from the savings account. Even though it is in-hospital, and PMB condition. I spend hours of my time on the phone with the call centre, trying to consolidate the accounts. My sister even paid some of the bills out of her own pocket to avoid being handed over to lawyers by the medical service providers, and now she can't get that money back. This is beyond ridiculous. She is so stressed with a very ill baby, and now she has to spend her time and energy fighting for a service she pays for.