UC phone assessment and how to complain

Hello I hope you can help. my daughter has waited 11 months for a telephone assessment for UC. I waited in all day. The. They rang to change it to later in the day. When they hadn’t called I rang and they said that I had missed my appointment. My phone was in my hand all day waiting. They have now sent me a face to face appointment instead of the phone call. how do I complain about this. I know nothing about UC or the process involved. my anxiety is through the roof. Any advice would help.
Than,s

thanks gary i will look it up .
debs