Bad customer service

I won a voucher which I used on the 11/12/2024 at KFC my order was given to a driver which never delivered my food .i contacted kfc several times from calls and tik Tok to emails till date 04/01/2025.no response always saying they will investigate while I have all the proof .very poor customer service.i even have sms when my order was cancelled what is the delay .i now lost my voucher all for nothing very ridiculous .everytime I get investigation excuses