RealPage is one of the great unrecognized villains of the modern age.
Fun story, a few years back I caught my landlord overbilling me on utilities. I said hey I did the math and you owe me back $X and I'm not paying any more utilities until that amount I'd been overpaying has been used up. My landlord used Realpage for billing, and Realpage said no that's not how it works, we'll get it corrected but you need to keep paying what's in the system or you'll be delinquent. I said go fuck yourself, I have no reason to trust that you and the landlord will adjust it accurately if I give you more money, I'm not obligated to wait until your system figures it out, your system is your problem, not mine. I plan to pay amounts I actually owe and not amounts I don't. They said you really have to. I said hey check it out I think I don't, let's see which one of us is right.
We went back and forth about it for quite some time, including me telling my bank not to accept withdrawals from RealPage (since they started charging me even with emails expressly explaining that they were not authorized to), which made them even more irritated at me and charging me extra fees. I said dude I am more than happy to explain this all to a judge if you want to go that route. They said you really have to pay though, we've worked out the overbill and corrected it but you still have late and returned-payment fees. I said we went over this, go fuck yourself, did I stutter.
When I moved out my landlord tried to not give me back my security deposit until RealPage was happy with my utilities balance. I waited 31 days and then sent them a formal notice that if they didn't return my security deposit I was within my rights to take them to court and get paid triple and planned to do so in 7 days. They said it had all been a big misunderstanding and was there really a need for all this and gave me back my security deposit.
Just talking about it now again makes me amped-up and irritated.