Marketing spam with no straight forward way to unsubscribe

I am not a customer of FNB and never consented that they use my details to send me marketing emails, but every now and again I get marketing spam from which I cannot unsubscribe without signing up with them.

The latest email starts off by saying that "You don’t have to bank with us to take up an FNB Funeral Plan." and then proceeds to try sell me something I don't want or need, seemingly aware that I don't bank with them.

When looking for a way to unsubscribe you only find this: "If you would like to opt out, go to the FNB App > Menu > My Profile > My Preferences to set your preferences.", and no other way (the email they sent this from is ***).

I am not an FNB customer and I won't install and use your app. I do not consent to getting your marketing and I don't appreciate you forcing me to install a piece of software to unsubscribe from your spam. I believe this violates POPIA by not giving me an opt-out that is easy and free from unnecessary formality.

You do NOT have permission to use my contact details for marketing purposes and if you obtained this by some underhanded means, then regard this as notice that my consent is withdrawn under POPIA 11(2)(b).