Can you turn the music down?!

So a family comes into our pub and even before they order a drink they come over and say are you going to turn the music down? We said unfortunately it's set at a level and we can't turn it down. They then said if we don't turn it down they will leave the venue! We already had lots of other people in the pub who had no issue with the music. They then bought a drink and then just carried on moaning about the music and then left. I mean when I go into Asda and do my shopping I asked them to play my top 10 rave play list but for some reason they never do! Who goes into a place and demand for the music to be lowered! If it's to loud go to Wetherspoons ha ha