The key to a good note is to let the person feel that you are really thinking of them. A good note keys into the person it's being sent to and reflects a special connection. (If you're writing to someone you don't know well, this is even harder. But I'll get to that later.) 1. Don't write the note when you haven't got a lot of time to think and ...
Dear Customers. We, the employees of this office are going to take our days off from the 25th of December to the 5th of January 20XX in lieu of Christmas and winter vacations. Your needs are Supreme to us so one of our representatives will be available 24/7 in case of answering any query you may have. Feel free to contact us on the following number [X].

Tested to/from 2 iPhones (1 personal/1 work phone) and neither of them receive the designated Auto Reply Text. What am I doing wrong?
I wouldn’t be offended or consider saying anything to anyone who included this in their out of office message, but even as someone who is in a religion that forbids use of electronics on most holidays, I still think this message is 1) TMI; 2) doesn’t convey what it needs to convey unless you are explaining that you don’t use electronics during holidays, in which case you can just include that you won’t be checking email without including the religious explanation; 3) would come across to me as inclusion of personal information I don’t need, which would therefore strike an unprofessional tone,and I wouldn’t understand why you felt the need to include that info. How about “I’m out of the office without access to internet or email until (date). If you need assistance before this date, please contact…” Like I said, I think your colleagues are overreacting, but in general I would advise to leave all personal information out of your auto-reply — vacation, medical leave, religious observance, etc. — people do not need to know why you are out.