Meat starting to have smell

I have accepted the fact there is nothing I can do about it but I am soooo angry and dissatisfied. A absolutely adorable friend of mine went to woolworths N1 city and bought me a lamb pack. She had a few other errands to run in the mall and then came to drop off pack. Honestly I was so excited because we can't afford to buy lamb and the fact that it's woolworths lamb made it a real Christmas treat. After convincing my husband to braai I took 8 chops out when rinsing they felt slimy but I just rinsed then I smelt it and it definitely had a staunch to it. Can you believe it, it was starting to go off. I was so upset actually a bit teary. I boiled it and gave it to our dogs. I know I don't have a slip and really don't expect to get another pack. But please please check your stock people save whole year to treat themselves and to have the meat start going off. I don't know if it's because she had a few things to do in the mall. But still. I have cut my loses and definitely won't be telling my friend but all I ask understand to buy your food is such a treat and when this happens it's so disturbing. Please check stock and ensure it's kept cold.