Sixty-one-year-old Hadley, from Pembroke Dock in Wales, began cheating the system after suffering a "serious stroke" in 2010, the BBC reported on Friday.
Having been forced to stop working for a catering firm he had set up in Spain, he claimed employment support allowance from the UK's benefit agency along with housing and council tax aid.
But Hadley failed to inform UK authorities about his Marbella property, even though he was repeatedly asked both on paper and in person if he owned a second home.
He was caught out when the UK's Department for Work and Pensions sent him a "habitual residency claim", demanding an answer on his other property.
Hadley, who pleaded guilty to three counts of benefit fraud at Swansea Crown Court, had managed to amass €31,500 from the British welfare system.
The Pembrokeshire man now faces nine months behind bars if he fails to sell his Marbella property within the next six months.
"He does find himself in a very difficult place as a result of his actions and, of course, he only has himself to blame for that," Hadley’s lawyer Jim Davis told the BBC.
"It is not an easy market," David added, in reference to the fact that Hadley had been unable to find a buyer for his Marbella property even though it had been for sale for several years.
The Swansea judge also ordered Hadley to pay £1,200 prosecution costs.