I'm also experiencing suddenly loosing customers, there doesn't seem to be any connection as they are in different areas. So far reasons are:
Father in law recently retired and will now be doing them.
Partner unable to find a job (luckily he didn't take up w/c'ing).
Didn't like having to pay two months bill.
Winter/Christmas coming, as it does every year.
So no similar reasons, guess it's all part of the type of service we provide, a luxury not a necessity.
So it's out looking for new customers to make up the shortfall.