"Shocking internal communication"

My Mum was referred to ambulatory care later discharged that day. 2 days later Mum was rushed to hospital and admitted to short stay ward. I received a call to say she'd been transferred to coronary care. I got there and asked reception where coronary care was. The receptionist didn't know and told me to go to the short stay and ask them where they took her. I replied it would be easier if they telephoned them and asked. This was done and then Mums details looked up. I was told Mum wasn't in the hospital and she was definatley discharged a few days ago. I told them that Mum had been in hospital for 3 days! I finally found out coronary care is in fact critical care. When I asked who updated the computer system they didn't know. I then asked how on earth my Mum isn't on the system when in fact she'd been there for 3 days and was now in critical care? I was told that I could fill a complaint form in. This is appalling that the hospital admissions do not have somebody recorded as admitted but even worse that they are in critical care! I'm so appalled by this and also by receptions attitude. Telling me to fill a form in isn't good enough, it's far from good enough. Adamant that Mum wasn't in the hospital.

How are you going to solve this please?