What to do when reasonable adjustment is withdrawn

Hi, I don’t know if anyone can help on this but I moved house and had to join a new gym a couple of years ago, because I’m highly sensitive to my environment I tried out quite a few first and found a small private one that played music at a nice low volume and was mostly empty or rarely more than a couple of other members present, I explained my ASC and they were happy to reduce the music or even turn it off when I was training alone or the only other people were wearing headphones/earbuds, however some time ago they increased the music volume and said they were no longer allowed to reduce the it even when no one else was there, I asked them to at least return the general volume to the previous level and they increased the volume even more so that conversation is almost impossible and even noise cancelling earbuds can’t block it out and I don’t like to wear these anyway as they affect my hearing and tinnitus, I explained how stressful this is for me and that I also suffer with anxiety and depression and how important my workouts are for to help with this, it’s not only while there but also it’s on my mind now all the time, I asked them for a legitimate business reason for declining my reasonable request which had previously been allowed with no problem, almost every member is wearing headphones, is there any action I can take to challenge their refusal at a more official level?