Are you receiving invoices and pictures of all work?

Get a detailed accounting of everything that has been fixed in the last 5 years and compare it to new invoices coming in.  

They get a unique account number, only for them, however I control the account.As mentioned prior, we have had issues with previous tenants making partial payments, but we have  withdrawn the funds and return them to the tenant with and invoice.

Communicate immediately in a form of an invoice that you'll expect the rent due, also whatever penalties and late fees your lease agreement allows.

Send them a bill for the situation and if they don't pay tell them your sending the invoice to a collection agency that will call them constantly till they pay. 

Dang it The tenant pays her rent every month. 

I asked for an invoice, and got nothing there either.

Here are some requests I already know about:Water invoicesProof current tenants are paying their rentRecent invoices from improvementsLease agreementsProof that own has 1st/last/security in proper accountsIt has 2 gas meters and 2 electric meters, so assuming that is covered by tenantthx!!!  

Give back the threat to sue them for your interest increase/difference on your transactions due to their unfair credit reporting, if they report it, you could call the bureaus and have it called off, then add that to the lawsuit, hire a credit repair service so you will have a paid invoice transaction. lol, all this for $100.

Dang!