You don’t ‘decline’ these. You ask “When do you need this?” Get the date and then say “I can’t make that date.” and leave it at that.
Time to stop turning the cheek and start kicking Butt. These fruitloops are going to wish they stayed in the closet when the screw finally turns.
I think I might have baked the cake and accidentally dropped it the day of the wedding...
Ooops... Sorry... but dont worry... no charge.