Lisa,
Although we are strictly commercial, we have had occaisions where the prospective client, has not shown the slightest interest in what we have to say or listen to our advice.
On these very rare occaisions, we just thank them for their time, and walk away, we do not even complete the survey.
On no account we we attempt to complete any job, without ensuring that the client knows exactly what work will be carried out, and under no circumstances would we start any work without a signed contract.
As to your present situation, has she contacted you twice? Sounds like she has from your post, so I would guess she is/was pretty well p*****, so, if it was me, I would send her a letter, containing a 50% refund, and explaining that this amount was in full and final settlement etc, etc. and that by cashing your cheque, she accepts this.
Cleaning is a service industry, it is not good that you ignored this situation, this should have been dealt with quickly, and be all done and dusted by now.
Lastly, dont knock yourself out over this, some peoplehave this sort of attititude, the trick is to recognise them and politely send them on their way.
Regards,
Rob