I do understand where you're coming from OP. You put a lot of effort into preparing everything for Christmas and clearly aren't getting much in return.
Away from gifts. Your teens should at least be helping with the decorating and any other Christmas preparations that they can do.
I'm really not into using gifts as a way to show love and appreciation. I think it should be shown through everyday actions like being there for someone. I do buy gifts, but I see it as something nice to do rather than as a way of showing love.
My mum is really into gifting, she gets excited for all occasions. One Mother's Day, my sister and I bought her a perfume online a week in advance but it took longer than expected to arrive. It wasn't there on the day. My other sister was on holiday and had forgotten to prepare something in advance.
I was in my first trimester of my pregnancy at the time and a bit scattered brained. I hadn't sent the card until Saturday afternoon and it wouldn't be there on the day either. My sister that wasn't on holiday was planning to give her card to my mum in person on the Monday as they were spending the day together.
It was a series of circumstances that meant my mum had no gifts or cards on the actual day. I live 2.5 hours away, so I couldn't just pop in to see her.
She went crazy. She cried, locked herself in her room and said she felt unappreciated. My dad rang me and told me how selfish we all were to have not planned something for the actual day. It was horrible.
In the end, my sister (that lives a lot closer) had to drive down and give her the card on the day. She cheered up.
This situation is obviously different as me and my sister didn't forget. I'm telling this story to show that gifts don't mean the same thing to everyone. My mum doesn't understand when I say that I really don't mind not getting something for my birthday or Christmas. I don't understand why she is so invested in gifts. We all try to muddle along though and get it right most of the time, but a little slack every now and then would make everything a lot dramatic!
You've made your feelings clear OP. I would get your family to help out on Christmas day but continue as planned. Forgiveness is an important thing to teach your children too, especially at a time like Christmas.