Not Impressed

I bought a 2litre Oros juice which had a competition running. It said I will get a unique number on the reverse side of the label. When I opened it the characters +27 (31) ***were not clear, I could not figure out the unique number. I then called the client care line where even after having not finished what I wanted to say I was offered a voucher! My argument is what if my code was for winning the trip or the cash prices? I would never know. Was told the manager will call me. She called me Monday morning saying she has a unique code for me, I don't know where she got it from and it was not a winning code! She said it's not within their control, I mean it now means I will never know if I'm the winner of the cash price ect.. I'm truly not happy, and I'm not happy with the way all this was handled. I was called from this number 27 (31) *** have since forgot the managers name who called me! I think it's just unfair