If you’re suffering, perhaps your neighbours are too. Consider forming a TRA or Leaseholders Association, which will lend weight to your complaint (sorry that no other solutions leap to mind – others might have better suggestions?)
Also, make you sure keep a note as to the complaint reference to check that it is being processed correctly. You might also want to speak to your local councillor to see if they will take up your case.
There are guides on all of the above (forming associations and complaints) here: https://www.leaseholdersforum.org.uk/guides/
Best of luck,