I stopped doing free talk lessons because there were a lot of issues/problems.
There were problems with attitude and motivation, and I got fed up with it.
色々な問題が発生したということで、「issues」や「problems」でいかがでしょうか。
「Issue」は「problem」の類似後で、「問題(点)」という意味です。
I stopped doing free talk lessons because there were a lot of issues/problems.
冷やかしが多いためフリートーククラスはやめました。
「What kind of issues?(どんな問題?)」と聞かれたら、詳細を教えてもいいと思います。
There were problems with attitude and motivation, and I got fed up with it.
態度ややる気の問題があって、飽きました。