You're working by looking after their pets, keeping their pets company, and by looking after their house.
Dettering burglars, available for deliveries etc yet you're expected to pay for the privilege!!
I've house sat many times and have always been paid for it.
Usually the most of the school summer holidays, so around 6 to 9 weeks.
It is a big job as you can't be as lax with things as you would in your own house.
We were able to sort a leak at one time which would have been a nightmare to have not been detected for when they were away.
Another time, the son had left his vilux window wide open before heading off on their holiday and we arrived to find his bed drenched after some heavy rain. Took ages to get it dry and avoid it getting moldy.
Cat needed vet attention once which we sorted.
Cleaned after ourselves when we left and always left some fresh bread, milk and eggs for them.
Although a beautiful house, you can never fully relax as you're always on the watch/worrying about the animals dying on you or getting lost.
Our rate was £200 a week as a couple but they'd leave extra for emergencies and pet food., always left wine for us as well as a bit of food.
One family didn't pay and when they asked the next year (last minute as they expected us to jump at the amazing opportunity) we declined.
Couldn't get anyone else so they had to leave their dog in kennels which cost a fortune, unfortunately had their car stolen whilst away so learnt the hard way.
Your people must be rubbing their hands with glee to have found you OP.
Never sit for them again.