Basically the NOI is the rent less OPEX or Operating Expenses. but not including debt servicing.

That's not the service we look for with the vendors.

Just as if you took that $100K loan from a bank.How you "service the loan" is up to you and the seller. 

We choose to manage our clients' entire portfolio (as long as it's in our service area), regardless of any of their properties being in less-desirable areas.  

That said, please be sure to follow forum rules and not solicit in the forums outside marketplace or spam via the message system, both of which are against the terms of service here.Based on your initial post, it sounds to me like you have more to offer than most so in my opinion, you have a better chance since you have the skill set AND some skin in the game!

You can even set it up with a servicing company so everyone knows that the payments go where they need to.

I am researching and considering using an online service to help with rent collection, statements, and other administrative management tasks for my rental property business.

This is partially due to the Urban Service Boundry. 

Odds are your lease requires you to pay the water bill and apparently you cancelled service, so he is now billing you for the cost up until the new people moved in.

I have used services like Cozy.co in the past to collect rent - but not sure about the application fee.I know that plenty of services will do the screenings for you, but I don't mind (and actually prefer) to be the one who vets each applicant.