Hi Castiel,
I've done some digging on this problem and found two posts about the maid service:
Problem with the maids on Sims 4
http://answers.ea.com/t5/The-Sims-4/Problem-with-the-maids-on-Sims-4/td-p/3602731Maid stops coming after a few days
http://answers.ea.com/t5/The-Sims-4-Bug-Reports/Maid-stops-coming-after-a-few-days/td-p/3464471Both of these problems have been going on since nearly the beginning of the game. They have been reported as bugs, and are being looked into from what I understand.
This may be due to routing issues - If the maid cannot route to do a job they will stay at the mail box.
Suggested to try:--- Check things objects above sinks and/or windows and mirrors directly over sinks can cause routing to wash dishes to fail. Books on a shelf too high up on a wall. These problems can cause the maid to fail and also your Sims to not clean properly.
--- Move the family out and back in.
If you find you have this bug, please go over to answer.ea.com using the links above and click the Me Too button.
Hope this helps, and Welcome to the Forum!!
MrsFlynn