Subject: money owed for unpaid <rent/bills>

To <your flatmate’s name>

I’m writing to let you know that you owe <me/us> money for covering your share of the <rent/bills>.

Our agreement is that each tenant pays <x> in bills and <x> in rent each month. You have not kept up with this agreement and now owe <x> in bills and <x> in rent.

Please pay this money back by <add a deadline that is reasonable>. If you do not pay [me/us] back by this time, <I/we> will have to consider going to court to get the money back.

<your name>

<date>