Billed on a account I’m not using .

I have opened an account with discovery and never ever used it until last year Jan when I realised I have been billed by charges. I paid R400 into the account so I cannot be on minus . Life gone bad on my side and I deleted the app and forgot about it . Only this year after I signed up for vitality someone showed me how this are linked up and I had to re-download the app , boom R2450 I’m owing discovery bank , I thought if the bank notices that you inactive member they cancel your account. I won’t recommend this nonsense to anyone. How do you still bill me for something I’m not using ? I called them to ask if they have a retention offer for me and they denied.