Complications with profile update

I took out a policy with momentum I now want to update my vehicle details and the people at customer care cannot update my policy. I have to collect my car today and I was told that there wouldn't be any problems. I am a new customer and it is unprofessional to get this kind of treatment. I want my issue resolved or I will take a different insurance. I just need my details updated do that I can collect my car today us that too much to ask for.