Completely missed "guaranteed Christmas delivery"
Ordered whilst they had a "guaranteed Christmas delivery" banner up, received my order in January. Had lots of back and forth with their customer service person about a partial refund, but the best they could do was 25% (increasing it each time I rejected their offer despite them saying at the time it was the best they could do). Lodged a PayPal dispute which was rejected because apparently PayPal only care that the goods are what was described, not whether the seller's timelines were as promised.