Quote from @Henry Lazerow: They eliminated the co-op to make the home more affordable?

For some context, the current payment is 30-31% of our gross income, we both have 780+ credit scores, no other debt besides this mortgage.

I’m currently working on 58 unit BTR development project and seeking one or two private debt investors to help fund it.

I recommend that you talk to a licensed debt collection company or a law firm on collection action.

We own 7 properties that we will start developing in 2025.We are currently remodeling my wife’s two-story home, turning that into two rentals.A developer contacted us and is using our largest plot to build a four-story condo building trading one condo for the opportunity.We drive and live in an 18 wheeler debt-free saving up capital for the next opportunity. 

Also be mindful of existing or proposed restrictions - I don't recall anything extreme proposed in Ludlow or Dover, but Wilmington is being very aggressive in all but eliminating STRs.

Best to change the locks anyway to eliminate any risk or perception of risk with the prior owners (or prior residents).

Our debt include only our primary, the duplex, and credit card $3,175.91+$7,317.49+$2,000=$12,493.

Current Debt?

I considered syndications which invest in car washes, self storage, multi-units and real estate debt funds but to be more passive but I've heard mixed reviews about syndications.