I had a domestic customer like that once...
Picked them up canvassing and agreed to an 8 weekly clean. Did the first clean, they weren't home but posted me the cheque with no problems.
8 weeks later I clean them again (as agreed), they weren't home again though... I waited a couple of weeks for a cheque to appear - but nothing... So I popped round to see them - They said "no, we only wanted it done once!"
I tried to explain to them that they had agreed to every 8 weeks but they were having none of it... In the end (after a bit of an argument) we agreed for them to pay me half the cost of the clean (it was a £25 account).
As I left he said "I'm sure we'll call you again in about 6 months when they need doing again"... I just smiled and walked away.
I'm looking forward to their phone call.
Andy