Impossible to Cancel Vitality

My husband and I are leaving South Africa due to work for a year and wanted to cancel Vitality. It provided to be impossible. My husband has first called Vitality on 20th May to notify them of cancelation, the customer service agent have confirmed that the cancelation will be processed. The agent promised to send him an email and did not. He called to confirm in the beginning of June, he was told by the first agent he got hold off that there was no notification on the system and then she transferred him to a different agent who did confirm that there was a notice and he can send the cancelation email, he did not. My husband called again today to check and got a new person who said that the are no cancelation request on the system and he can put in the cancelation but because Discovery needs 30 days notice they can only cancel end of July. This is very poor service and although Discovery records all calls they have not provided call references to my husband that he csn use to fight his case that notification was done in May. Now we are forced to pay for extra month because Discovery Vitality agents are ***********, surely they can search the system on their side to find his cancelation request on 20th May if the calls are indeed recorded instead of messing him around with the request that some agents can see on the system and some can't?