Another issue with spar varnish, perhaps related to the long drying time, is it will off gas for weeks or months. Not an issue when used outdoors but...
Again, not familiar with them, I assumed you could take in to a shop, have it repaired and reinstall it yourself, obviously the only part I got right...
I don't disagree that he should fix it just that there was a misunderstanding when you said you would get it fixed and assumed he would hear "and he...
Perhaps when you told him you would get it fixed you should have added "and send you the bill." It's not that unreasoable for him to assume you were...