Screening is now more important than ever and I am less likely to take chances than I was which should result to fewer problems in the future.  

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

Up until now they have been model tenants that were properly screened.

I'm more likely to read a computer screen/phone/tablet...i guess i need audiobooks or invest in a large tab!

Otherwise, I have the same screening requirements of everyone, and make sure that my screening criteria safeguard against risk, and don't screen out people based on any status that wouldn't matter, like immigration status.

How would I go about screening applicants and collecting payments?

If they are not, and are just habitual poor paying dudes then it's the management company not screening the credit and background.  

@Charles Carillo I took a screen shot, I have two more books to read then I can start picking from that list, thank you for your input, and congratulations on your success.

I use it as a general screening tool.  

No matter the size of the new loan you have flat fees: underwriting, appraisal, plus title and escrow, recording, notary the same as when you started the loan BUT you do not have any seller contributions to subsidise part of the title and escrow/attorney costs.