Poor customer service, inefficiency and slow processes

I have been trying to cancel Discovery Vitality for a few weeks now. After 4/5 calls and multiple promises, Vitality still remains active and the debit order keeps going off my bank account. I'm really disappointed with the service received and; as a Discovery Life holder; I'm concerned about what the service would be like if an actual claim needs to be made. I would like someone senior to make contact with me to resolve this immediately.