Credit card interest so high with no explanation

I have a credit card with fnb so I asked for my interests to be reviewed and lowered they told me to wait 6 months I did that ,after the 6 months I asked again they tell me they can't lower it telling me it base on my credit scoring I should wait another 6mnths . That's the part I want clearity on. my scoring is more than 800 so I don't understand based on what is my interest so high 22%. When I send them emails, they don't reply,Asking why is it so high. Based on what is it high.