Why, before leaving the house, did you not ensure they'd cleaned???
I was the last one for the last 2 years too, and whilst this year everyone did some cleaning, I finished it off, even if it wasn't "only" mine.
Last year they were pigs, and I also cleaned what was left. One of them left a carful of stuff - I made them come back and get it all.
You shouldn't have waited till now, and you're using the same excuse as my aforementioned lazy housemate did - presumably you finished weeks ago, just because you left it to the last minute doesn't mean you didn't have time.
When you leave last, that's always gonna be your job to check.
If it was their rooms it would be different, but presumably you have in the year used the communal areas.
I still wouldn't pay it all, but you did make large errors here IMO.