Collecting rents is an art and a science.What you should depends on where they are with their late rents.

Many opt for other investing methods in their SDIRA like private lending, crypto, private equity...anything except collectibles and life insurance.Note that a Solo 401k is exempt from UBIT on leveraged real estate so if you have self employment activity and no full time employees save for you and your spouse you should consider the Solo K as an option. 

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with little, maybe even negative, relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560 (almost 30% probability of default), little to no good tradelines, lots of collections & chargeoffs, recent evictions.

@Adam BartomeoAny recommendations for the collection agency?

Very difficult to identify 2% deals in areas where you can consistently collect rent with any kind of predictability. 

That's why tariffs are always collected from the business that is inside the country.

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with little, maybe even negative, relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560 (almost 30% probability of default), little to no good tradelines, lots of collections & chargeoffs, recent evictions.

When you can borrow 80% tax free and continue to collect the income?

Just a point of fact Class action suits are a pipe dream at this level in almost all circumstances. there has to be money to collect.  

@Jay HinrichsMost of the investors are not sophisticated enough to create IRRs.