Chicken had a bad smell and looked disgusting

I bought a packet of chicken drumsticks. The once that look like kfc chicken. I took it out of the original outside packaging but kept the original zipper bag and had in thr freezer. I did check the expiry date but it looked fine. So the day before yesterday i decided to make it for supper and when it came out of the oven it had a really bad smell and there were some wird black marks on it. Had no other choice but to dispose it. I was really unhappy as it completely put me of my hunger resulting in that no one ate of it and the food we prepared with it going to the bin with all that chicken. Not really happy with the chicken especially not with what you have to pay for it. I do have supporting images. Should some need to speak to me about it please could they do so after 4pm in the afternoons otherwise i cant answers my phone.