The provider I'm currently with isn't able to send me anything via mail, I've tried 3 different addresses and non seem to work for them.

I'd say go in person to the PO when you mail, so you can get a receipt...that shows when you mailed in a reasonable way....I notice when you have a nice file when you go to the eviction hearing your chances of winning seem better if the tenant shows up...because chances are they will not be prepared. 

Direct mail.

Can someone point me in the right direction when it comes to getting addresses to mail homeowners?

Don't just call them once... make it a point to remain in regular contact with them (at least 1x per month) via phone, face to face, email, text, social media, mail, etc.At the same time, make it a point to add X number of NEW contacts to your database each day or week.

We have a PM and communicate wiht them. when we did not have one long ago we did not have any app or anything. we had them pay online or mail a check and put $ in quickbooks and if there was an issue they would call or email us.

@Nigel YarbroughTo find cash buyers and structure a lucrative deal, join local real estate investment groups, contact agents, search public records, attend property auctions, use online platforms, connect with wholesalers, and send direct mail campaigns.

VA law just requires US mail. 

I will send you two copies of the publication if you provide me with a mailing address.Thanks for the support of our fellow investors. 

After you are up to speed, please reach out to me directly by e-mail or phone.