Charity shops in Leeds have been warned not to sell Christmas cards early or face having their locks glued up.
A Mind shop in Headingley has already had its lock glued, while other shops in the area, including Oxfam stores, have received a letter from someone claiming to speak for the Movement for the Containment of Xmas.
The letter warns they could have their locks glued up if they display Christmas cards before 1 November.
A spokeswoman for Mind said the targeted shop had made £50 selling Christmas cards from old stock in recent weeks, but the vandalism had cost about £100 to repair.
"It's had a horrible effect on staff," she said. "They are quite distressed and worried it might happen again. This kind of activity is bullying and is not acceptable."
Clive Barker, shop manager at the Oxfam store in Headingley, said: "We stock and sell cards because our customers come and buy them year after year. We have sales targets in our shops to sell cards so we can make as much money as possible."
Barker said the store was operating business as usual despite the threats.
Police are looking into the matter.