The rent by room was managed by a company which I no more trust and started exploring other options 

I'm currently an investment agent and in a position financially where I'm ready to start with my first investment property.

These types of tenants often do this because they don't want to save in advance, so they take the rent owed to you and use it to put down on their next home.Recommend you do a better job of communicating to the tenants that you will pursue every legal collection option if they don't pay last month's rent.Also, why are tenants NOT staying with you?

You need to identify your starting point to determine your options.  

Let me know if you need some good options here; we work with quality accountants all around the country.   

If they don't - then it's optional.  

Are there options for assuming the existing mortgage and financing the remaining balance with another mortgage?

By the time I closed, I had tenants moving in that same week at positive cash flow.

:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+, zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680, some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

Despite the Interest rate and Housing Crises, there are many people who are realizing the importance of Cash flow and Passive Income, and with current Interest rates, is it Realistic to seek a Cash Flow Positive rental investment, considering that you have bare minimum equity in the Property?