Can't spend ebucks at KFC

I went KFC with the aim of using my eBucks to purchase a meal, but to my surprise the eBucks card didn't support making a payment and I had enough balance. Why can't I spend my eBucks at KFC? Do I even earn the ebucks when I purchase there though? This happened in different occasions. When I contact the secure chat via the app I am told that I can't be assisted I need to call ebucks department