Soundproofing door

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I recently moved into a flat which has a shared vestibule with one other flat. The tenants in the other flat frequently have arguments in the lobby and I can hear everything through my door. I hear them locking and unlocking their door and its very disturbing, especially some nights when its continuous for hours into the morning (I have no idea what they are doing). I have asked various joiners what they can do for me but none of them are willing to guarantee a new door and seals (has to be fire rated) will definitely make any difference.
As a result we dont get on as neighbours, so its pointless asking them to be quiet. I've tried the adhesive insulation strips but they are rubbish.
Any suggestions, I'm getting desperate for a good nights sleep?