Here is a question to the blog clinic from Nat who is a landlord:
One of my tenants has just moved out and I have realised that a change in my rent collection system (I changed the rent due date) in 2006 resulted in an underpayment on her part.
She maintains she has paid every month since she has moved in but can’t prove it because her bank does not have statement details before 2009.
I have offered to waive the money owed from 2006 if she pays the sum I believe she owes as a final settlement. She is adamant that she owes nothing and is claiming that I actually owe her a refund.
The best way to prove the underpayment is to do a proper schedule of arrears. Do it in a spreadsheet (eg Excel) and do a separate entry for every day the rent fell due and every payment made by the tenant, with a running total up the side.
For a tenant who has been in the property a long time it may be a long job, but it is the only way to prove the arrears.
It should end up looking something like this