They are going back on their own T&Cs. They refuse to refund my premiums

The terms and conditions of my cover states that in the event I cancel my policy, the following conditions will apply with regards to the refund of premiums: The will be no refund due if a claim has been paid under my policy. I just called today the 13th march 2025 at 15:20 and spoke to a Quinton who boldly told me I will not be getting a refund on my premiums despite the fact that I have never claimed on my cover. Now I need to know how and why I will not be getting my premiums back / isn't that breaching your own terms and conditions ?