Bad service

I bought a meg ****in with juice on the 03/11/22 at Mc Donald's maponya mall, take away, I ate the meg ****in first while on my way to another centre and finished it, then when I was about to have my juice, it tasted like water and I had to turn back to return it,when I got there they requested that I also return the ****in which I already ate, so they then said they will give me another juice which I didn't want, I wanted a refund. The supervisor refused to refund me, I also wrote a review on their website and no one has returned to me.