There is a lot of whining this time of the year about how no one is in the office, and there is no work that a salesperson can reasonably do. It is not true that "no one" is at work. And there is always work you can do during the last two weeks of the year.
If they are at work
A lot of the people who you need to call will be out during the last two weeks of the year. They will take time off for the holidays, and they may add vacation time on either end of the holidays.
Just knowing that people are gone can sound like tough sledding. It's difficult enough to get your prospective clients on the phone during a normal work week (you are using the phone, aren't you?), let alone making calls when many people are not at work.
But some people are at work. And those that are at work have very little to do. Many of them are simply killing time, cleaning their desk, and organizing themselves for the next year. Some are standing at the water cooler chatting it up.
The people who are at work have time to kill.