oxtail bought from pick n pay mall @carnival

I bought oxtail at pick n pay mall at carnival today around 10:20 am. There was no staff readily available to assist me so I assumed the oxtail on the shelf was fresh because the sell by date is the 10th of Feb 2015. The meat had a foul smell from the moment I opened the packet, but since it was my first time preparing oxtail, I thought thats how it should smell. The bad smell filled my whole house and wouldn't subside even with the oxtail being in the oven.I then decided to taste the meat once it was cooked and indeed it was off. I am very disappointed in this pick n pay and I was very embarassed as I was hosting friends who were meant to eat this oxtail for supper.