Catch 22

I am trying to cancel my Prime video subscription, which is linked to my internet fibre account. I have made numerous telephones calls to no avail. The last time I tried, I was transferred 3 times then cut off. I have visited the Telkom shop, but they could not assist. I am told to cancel on the Telkom app, which I cannot access, as I do not have a Telkom phone, so cannot receive the 0TP to log on. I am paying for a service I no longer require.