Were you able to communicate effectively with the contractor?

(completely understand but why did someone not communicate with the tenant?)  

The best ones for the very beginning in my opinion are Miracle Morning for Real Estate Agents and then 7L: The Seven Levels of Communication by Michael Maher.

They were on a payment plan but have recently stopped payment, gone no communication and telling neighbors they plan on squatting thru December due to CDC guidelines. 

I communicate they should let me know ASAP if there is an issue.  

If you communicate your goals to your realtor (to find a property to flip) you should also ask them to have an ARV with supporting comps ready for you for any property that they present to you before you even go see it because you will need that number in order to make an offer anyway.

It will be on your behalf, face, and voice:Build a relationship with the home seller by sending out useful content periodically.Communicate through the video with the seller to get used to your appearance and manner of communication.Adapt on the fly communication to the interests of the sellerCalculate the seller's motivation (lead scoring)Qualify a lid as warm or disqualify it:Read more in the article "10 Best Email Marketing Software Tools for Businesses".

Keep communication lines open, renegotiate when necessary.

Had to communicate a lot with potential buyers and come up with some different ways to show them how/where the property was located.

For free sphere building, my favorite book is 7L: The Seven Levels of Communication by Michael Maher.