Premiums taken after cancellation; refund refused

We issued a cancellation notice to Liberty last year, which they ignored on the grounds of \required documentation\". They already had the documents, having required them in order to issue the policy. Despite the cancellation request, they continued deducting premiums. They eventually cancelled the policy effective 1 February, but are still refusing to issue the refund because \"the outstanding requirements were not sent in time\" - the same documents they have had all along, and for which I have two emails from Liberty confirming \"We have retrieved the [document] on the system\".<br> ie. They had all required documents. They ignored the cancellation request for 3 months. They deducted premiums *******ly, and are refusing to refund these. This is *****!"