They did not forget; once it's in the system, it's in until it's acted on.  I am not sure of your question.  Did you get an interview date?  If so go to the interview, why expect a follow up call?  If not, wait until they give you a date.  If you've had the interview and want to know the result, there's nothing to do but wait.  There are reports to write and people who have to sign off and meetings where they discuss people, and calls about your application, etc...   

And it's the end of the year, so there is use or lose leave plus the holidays.