The holiday cottage with a boiler that broke down happened to me.
It happened second day and was fixed on day five. There was no financial compensation. The cottage company (very reputable) organised someone to come and look within 6 hours and the. A key workman came the next day and 2 days later the boiler was repaired.
It happened during a summer holiday so we didn't need the heating. There was an immersion heater which was a pain to use. However, the company were swift in dealing with it and kept us informed. We are also offered an option to go to another cottage 15 miles down the road after the 2nd workman came and it was clear it couldn't be mended that day and we would have to wait nother 2 days - we turned this down becaue we loved the location of the cottage. They did give us 6 bottles of wine on the day it was fixed.
It was annoying but no more than that. We weren't furious or outraged despite paying premium summer holiday rates. We just understood these things do happen and we did appreciate the level of service and communication and apologies the company gave us.
My feeling is that tenants are often a bit chippy. I understand why -they often have had bad landlords who haven't got on and mended things or communicated well. And they also often feel they are being ripped off with the rent. I think it is because of these things that some become very aggressive and to be honest unreasonable in their timescale expectations about repairs or espcting financial compensation for being without certain services for less than a week, when they have no entitlement to such compensation.
I think tenants often feel pretty powerless - often they don't want to be tenants but would prefer to buy and can't, often they are living in accommodation they don't especially like and often they have had bad experiences or know that bad experiences are pretty common. I think that when people feel a bit powerless and something happens, they often react in an aggressive or unreasonable manner. Sometimes it's also about simply not knowing a different way to respond to problems and how to interact well with people to bring out the best outcome.
TBH, I don't think the OPs tenants have been like that - they sound like they've voiced annoyance about the boiler issue - perfectly fair enough. OP needs to expect that in the circumstances and respond apologetically and be clear she is on the case and communicate timescales regularly. She is doing that.
However, many on this thread sound like they WOULD be stroppy and unreasonable tenants in the same circumstances. I don't know if that's because they have been tenants who have had bad LLs previously or if they are just stroppy unreasonable people in all areas of life who don't really have an accurate sense about what you can expect or what is even possible in different circumstances.
Shit happens, as others have said. It doesn't always warrant compensation. When you've paid you are entitled to a speedy response and clear communication and the problem to be sorted in a reasonable timescale....not blood and not impossibilities.