Personally I prefer subscription model over ad-based data tracking model. When you get something for free, you are the product being sold. For example Facebook or Reddit. Your content (comments, media) is used to populate the site and your data is sold to advertisers.
When you pay a subscription, you are the customer. There's more incentive to create a proper service with the actual users in mind when it's a subscription model.
When advertisers are the primary customer, they will always be a priority in determining policy. So for example YouTube- longer ads and more of them.
Of course, I think Google is guilty of double dipping. We pay for premium but I'm certain they still sell our data to advertisers. For example you watch a lot of carpentry videos, they will sell a list with your name that says "likely tool buyer" or something along those lines.
But generally speaking, I never mind paying a subscription for a service. It's more honest, more clear what's going on.
There are laws against excessive fees like this. In my home state of Florida, a landlord cannot charge more than 20% the rent in late fees.
And trust me, Florida is not known for its consumer protections. So chances are your state has a similar law which is probably better.
So if I were you I would look up the law and not pay.
Assuming of course you are telling the full truth- your full rent payment was late for a short period of time.