應不應該付錢 ??

家裏的水管沒了熱水，叫來Plumber，Plumber來了後，看了半分鍾，said hot water should be in left side, not in right side. (be fair, it was some kind stupid mistake we made), anyway, that was it (we used wrong side of handler). He charged us $105 for this. I thought it was not reasonable for this, I offered $50 for him, but he didn't take instead he threatened us to go to the court.

What do your guys think? Should I pay full amount or just ignore???

Thanks in advance.