Up to date policy terminated

I have been member of liberty since 2009 after I went on pension in April 2020 they send email that they are terminating my policy I told them not to terminate it then they stopped debiting I decided to pay them manually later I asked them to send me debit order form because I did not like paying them manually they send the debit order forms and still there did not debit. I have asked them again to send me order this week they said my policy is terminated. Please advice how do you terminate an up to date account? Did you inform me months before terminating? I have proof of my monthly payments.