I'm sorry you had hearing problems but you could have pointed this out to the guide or changed your location. It wasn't such a large group... As for the fact that you paid, it seems very normal to me, do you work for free? You should know that free tour does not mean that you don't pay but that the guide leaves the traveler with the right to value the work done by the guide. I think you know that a paid tour like the one you did has a value of at least €30/40 and you paid much less I think...am I right? Plus you also wanted your own earphones (at our expense of course). What else? A cappuccino and a brioche?