Refusal to pay a claim

I am insured with Affinity Underwriting Managers, in December 2017 I was involved in an accident upon lodging a claim with Affinity I was told that my policy was cancelled and the cancellation was due to a reversal of a Debit Order, I then insisted that I never reversed any debit order and I've since sent my bank statement to them that I've never reversed my Debit order but they have since not come back to me, if I had known that the policy was cancelled I would have taken up another policy, thus they should still pay this claim.