for those that pay online on a regular basis but may be a little slow i send this first
"Dear customer your windows have been cleaned today,xxxxx
We look forward to receiving your payment by BACS.
Regardsxxxxxxx"
I normally send this to people who are out, work abroad or just need the extra prompt, as well has the completion slip we leave.
Then after say 5 days.
"Dear customer there appears to be an outstanding balance of £xxx for your window cleaning dated xxxx.
If payment as been made please accept our apologies
Regards xxxx"