Post it on their door in a sealed envelope plus mail it via certified mail with proof of delivery. 

They don't need to be high-end and great deals are always available online from the big box stores with delivery included. 

That’s funny, I always thought PhD stood for Post Hole DiggerPizza Hut delivery guy 

It costs us about the same and is way more convenient (smaller minimum order, next day delivery). 

Your hours would be tied to a delivery schedule, tied to scope. 

They can be purchased online starting at $29 to $99 with same day delivery! 

I'll say the annoying part about that is an extra burden on you to timely deliver the bill and to create a fair payment schedule that may not correlate with the actual due date of the bill, which means you may be paying the bill before the tenant reimburses you.However, it doesn't sound like you have a delivery issue.

Once your list is scrubbed you will receive 3 different files.1) Single P File - These are the addresses that are incorrect/undeliverable from your mailing list and USPS is unable to deliver to these addresses.2) Move Update List - This list contains records that were updated to match the most accurate delivery address per the USPS records.

Keep a copy of the letter and the date and method of delivery for your records as this may be necessary for you to be able to prove when and how you notified the tenant, should the question arise at any time.I get the sense that you may be new at the landlord business?

Send the notice to the last known address - with address correction noted on the envelope/please forward - with proof of delivery requested.