So, I was tasked by client to help him convert his wp menu to javascript dropdown. I did on my development server. He did see the change and I was paid. I deliver the code he deploy it. But, no change on his server. So, I have to spent hours debugging it on his server. It turns out, his other plugin is not compatible with my change. That plugin is really custom. I have to change my code to make sure it's compatible with that plugin.
My question is, is it fair for me to charge him for the hours I spent on debugging it AND actually fixing it? or is it still my responsibility, to make sure my code deployed properly?