Beedrill

Yesterday I was playing a beedrill deck against a water deck and I used destiny stinger. I was checking for any abilities that may hinder its effects but there was none and I also had 10 damage counter on me so my beedrill dies but also the opponents pokemon is suppose to be ko'd as well but it was my beedrill used it and died and his pokemon wasn't knocked out either. He took a extra prize and I wasted a turn and lost. This happen to anyone else if so please fix this