Oliverson,
Sorry to hear of your bad experience when letting your property out. Reading between the lines, you have handed your apartment keys out to someone who has no official business, no office address, no land line telephone number and is working from the back of a car. I guess that you wouldn't do this with a second home in England, where it is much easier to manage, so why take the chance in Spain. When you enlist the services of a registered agency you have some protection in law and they are obliged in law to carry a complaints book where you can make an official complaint.
There is always risk when you rent your property out, be it holiday or long term, but if you use a registered agency, who have an established office, they can never run away from their obligations and should always be there to assist you when things go wrong and usually work closely with lawyers.
This message was last edited by ian on 30/01/2011.