In hindsight I would've also been better off leaving it open for assignment to cut those costs even more.

Tenants all leave, the only question is when.

I put down $10,000 on a 4 unit building and $8,000 on the duplex.  . so that still leaves me with $12,000 that I can play with and hopefully get another property owner financed . 

I will work on leaving notices and a timestamp on his door and mail to see how the delay in response is.

That's really the question.If the buyer does have a system for inspection, title research or other due diligence and leaves this up to wholesaler/intermediary, then you ought yo oasis until you are comfortable with putting am process in place.The wholesaler is negligent in being clear, IMHO.

Expenses on the building are about $100k per year leaving an NOI of approx $300k with the in place leases.

I also specialize in flipping Tax Deed Land Lots, Multiple Choice Offers and Seller Finance Rentals where both the Seller and the new tenants pay me which leaves me with a little cash flow while I wait for the mortgage balance to go down and the property value to go up during the 1 to 3 yr Seller Finance period.

Currently, I only own one rental property but I leave ALL incoming rents in one account so my monthly cash flow piles on each month and I could cover 6 months rent or so.  

I specialize in Wholesales, flipping Tax Deed Land Lots, Multiple Choice Offers and Seller Finance Rentals where both the Seller and the new Lease Option tenants pay me, leaving me with a little cash flow while I wait for the mortgage balance to go down and the property value to go up during the 1 to 3 yr Seller Finance period.

Tell them to take time and think it over and leave it on their car windshield/door.