Hi Dawnlee!Actually,most of the hotels,not to say all,are closed in the winter.Because you know Sunny Beach is summer resort.the tourists come for the sea and the sun.and in the winter it is empty and there is nobody.some of the hotels work but i also don't know why because there is no any people in the resort.
But for celebrating Christmas you can go in some of our winter resorts-Borovetz,Pamporovo,Bansko...I can reccommend Pamporovo,it is the best for me.eveb more if you like skiing,the tracks are very long!and in all of these resorts you can celebrate Christmas or New Year in the restaurants there or in the restaurant in your hotel where you will stay for example.this is...if you have any other questions,ask me;)Bye