Conversation M: What happened? I’ve been calling you for hours. Y: I’m really sorry I haven’t called you. However I was going to call you, but I couldn’t find my charger. M: There’s no excuse, you could borrow a charger to your colleagues. M: They don’t have an iPhone charger. Besides that, I had to work that much, due to one of my colleagues was fired yesterday. Therefore, now I have to deal with all his work. Y: Oh I see, well it’s not your fault. M: Thanks for understand, I didn’t mean to make you worry. "I would like to make it sounds more natural, what other phrases can I add? In order to improve it "