Bad service, support everything

loaded a gift voucher with R500 on Uber eats,and since last week Friday I've been trying to order with no luck,their help support,have been sending me from pillar to post,or even close the chat and say they've already helped me,even today my gift is stuck there ,can't use it cause at first it showed and error message and said I must contact Uber,which I did and got no help,now it doesn't give me option to buy with my gift,when i contact them am told,there is an investigation which they can't tell me about ,which suprises me ,cause it was my first time trying to order through Uber eats.worse they don't want to give me my voucher back,so that i can sell it or something.