Old powerbank

Sold me old powerbank, I bought a powerbank on Friday late,I then realised that the powerbank that I bought was old had scratches, even the package wasn't properly closed. On Monday I tried to take it back to Clicks Aliwal North, they refused to take it saying that I need to take it back to Bloemfontein. I was in Bloemfontein only for weekend, I can't just travel for the powerbank. I'm so disappointed and disgusted with this. I'm stuck with something old not sure if it had all the things that are supposed to be inside...