I regret joining them

Is it possible to rate them zero stars? Can I go lower? I processed my claim (after a taxi crashed into the back of my car) over a week ago and they keep promising me that an assessor will contact me but he never does. When I call in, they ask for my Whatsapp number that I have provided multiple times. They claim that their turnaround time to respond to emails is 4 working days but they actually respond on the 5th working day and their response is usually useless - rendering us to start the process again. They are definitely trying to stall the claim process and in the meantime I am frustrated without a car.