@Erica24 - You are in a tough situation since you've already said "yes" to letting them leave their bags behind. You are running the risk, too, of not just one bad review, but 2 - from the guests checking in who will have to navigate around a second set of bags in, as you admit, is a small apartment while trying to settle in after a long day of travel.
It is a tactic of guests to threaten to review you badly unless you allow them to do something outside the rules of your listing. This is extortion and against Airbnb policies. Make sure you are using the Airbnb messaging service to record all your activity with the guests. You may need to get Airbnb involved and this is the only way to accurately do that.
Based on your message, I am assuming you said they could leave their bags there in the apartment UNTIL the next guests arrive which is some time in the afternoon. If this is the case, my suggestion would be to let them know if the bags are not gone by XXX time, they will be charged a late check out fee. Send them the map again, if you can, and let them know the other option is to take their bags to the station.
Good luck!
Alice