Too much of late fees - what to do with tenants?
I rent out my house in Myrtle Beach, SC and 3 months ago a new family moved in. I was very loyal at the beginning and allowed them to pay half of the deposit 1 week later (they had some family emergency). They didn't pay it as promised, and brought only half of the rent money when the next month rent was due and asked me if I could allow them to use the deposit to pay for that month. I denied their request and told them that this money will go toward the deposit, so they still owed me the rent money.
They've been late on the rent money for a month and been telling me different stories and every time the money would be on Friday, or Monday... but never were.
I have a friend who was helping me out with the house for over 1.5 years now, but he is not working for management company, so there was not much he could do besides calling them and leaving notes in the door.
After I got fed up with my tenant's stories I hired a management company. They delivered a warning notice last week that tenants have to pay this month rent by Friday, otherwise on Monday the management company will file an eviction notice. So, the tenants called and told them that they will drop off the money monday Morning.
Now, the main question:
The tenants owe me $2,100 in late fees. If they pay the rent, I would assume they wouldn't play games anymore since the management company is pretty serious about evictions. Should I reduce the late fees in order to keep them in the house and at the same time still teach them a lesson? I realize that $2,100 is a great sum of money in late fees, especially when you pay only $1,000/mo rent.... at the same time I don't want to be a "nice guy" any more.
What do you think?
P.S. I'm new to renting, so I would appreciate any advice.

Well, the first eviction notices was served - the tenants decided to drag their tail and keep wasting my money that I don't have, so they applied for a court hearing, which was scheduled for July 30.
Some one told me that in some states if tenants declare bankruptcy, the eviction stops. I asked my management company about this and they said they never heard about it. While this law may not exist in South Carolina, it doesn't give me much confidence that I won't get in any further trouble with the tenants.
Does anyone know what's the worse thing I can expect to come out from this hearing? My management company assures me that the tenants will be evicted after the hearing.