Oh Theta. I know all about irritating and careless neighbours. Fortunately I don't have to deal with them anymore since moving last month, but it can reduce you to a Nervous Wreck. My neighbours once left their TV on for two days straight - day and night. My bedroom was below their living room. I was going out my mind, couldn't rest, couldn't sleep, pacing the room with insanity. I phoned their landlord who came to switch it off and it turned out they were away and would be away for FIVE days.

I also put a note next to the communal front door asking people not to slam it (my room was adjacent to the front door and shook every time somebody went in or out) which was promptly ripped down.

I can't imagine how upset I would be about the fridge/freezer, which I presume is especially important for your work. What would likely be a small annoyance and hill to climb for many is catastrophic and mountainous for us.

I hope you are able to get things sorted - it's unfortunate they are your landlord's relatives! Thinking of you.