team fight, Bug problem

playing team fight and had Elise on my team and was leading pretty well, until somehow two spiders jumped into my purchase champions, I couldn't sell them and when I placed them on the field they would disappear. had two champions spots taken up at all times, please fix this issue. I gave up when I was in 3rd because I fell behind, sold all my champs and just the spiders on the field and the enemy attack them like normal spiders. [zombie-brand-mindblown]