Debit orders went through for a contract that had expired

My contract had expired last year April. Netsart continued to debit my account and no one from their side had called to alert me that the contract I had with them expired. I am off the opinoin that I had tracker because the debit orders went through every month only to find out now that I was not corvered for anything. I am struggling to get my refund and received a poor service when I requested to speak with the supervisor.