It's a regular supplier, and I suspect the client knew what the invoice was for, which is why he paid it without question.

However, as you said a copy should be obtained before paying them. That's just common sense, IMO - doubly so when it's already spotted by the client as not being on the system (itself an indication that it hadn't been recieved), and confirmed by me.

When I next reconcile his accounts, that payment will go on as a payment on account, and added to my ongoing notes and queries file (shared with him via Dropbox*) saying that a copy is needed. Nothing will be done in response to that note until I next pay him a visit (printing out the notes and queries to take with me) and he'll then either send them an email asking for a copy, or he'll ask me to do it.

If the latter, there will be a few emails back and forth before they send me a copy because, as far as they'll be concerned, I'm an unknown third party and they won't initially want to send a copy of the invoice to me.

I know this, because it isn't the first time - hence the need to hit my head against the nearest wall.

* It used to be that as I reconciled things, I listed any notes and queries in an email for him to ignore, but he didn't like that - so now I put them in a file on Dropbox, so he can ignore that instead.

I have a hard skull, so I try to avoid damaging walls (which costs money to repair) and usually just bottle it up. Which is probably why I've been on tablets for stupidly high blood pressure for the last couple of years.

Using Dropbox was this client's idea - and TBH it's actually slightly better than emails: With the emails, I have to refer back to previous ones to see what queries are still o/s - even if bringing the O/S items forward into the most recent email, it still requires referring back to at least one email.

Putting them all in a single document in Dropbox works better, because I'm always editing that single document: adding new items as they happen, deleting older ones as they're answered. I have it neatly arranged: the first n pages are general queries, then a table listing all the CC payments I need receipts for, then a table with all the bank payments, and so on.

The funny thing is, as I said, this was his idea...

I started off using a document created in OpenOffice, saved in my client folder, and a PDF copy saved in the Dropbox folder - because, IMO, this should be read only for the client. (I don't want him deleting queries where he thinks he's answered them, but hasn't done so sufficiently).

He wanted it as a Word document, though. I argued the point, and he insisted he wouldn't do that - so as a compromise, I now save my OpenOffice document in the client folder, and save a copy as a Word document in the Dropbox folder. I can then see if anything's been deleted by comparing them.

And since we've settled on that, as I've said, he seems to have ignored the document - just like most of the queries in the emails got ignored; in both cases until I visit and go over them.

This is a big fan of cloudy-crud (hence the preference for Dropbox) - so it's a bit ironic, really!