Uber One "99% off" vouchers cancelled at checkout — no support reply in days

I have had 5 vouchers given me for a 99% off of my first 5 purchases on Uber Eats after joining UberOne and the code simply just doesn't work when you try use it, strangely only when one wants to pay it cancels it to pay the full anount. I have addressed this days on end and no one has come back to ne after saying they would after 6-12 hours. I'm highly disgusted in this because it's luring people to ger to that part and eventually just giving up and paying full price after numerous attempts. It's false advertising and it's disgusting.