Hobby Rewards Points

[Adrian-352009]

Everytime I try and use my hobby rewards points the vendor adds the discount back on to the final price. E.g the order is £24. Click the box to use my reward points and the website now says £20. Select PayPal. Redirects to PayPal website and the total to pay is saying £24. Same thing with Clear Pay. Not sure if the same thing will occur using my bank card as I'm to afraid to try it as I won't know what I've been charged till I look at my banking app by which time it will be to late.