15,000 people were invited via Facebook to attend the "Mr. Happiness" event held on Saturday on the outskirts of Fuentidueña del Tajo.
It was advertised as the "party of the year" but ended as a miserable evening for rain-soaked ravers.
More than 4,000 accepted the offer of €30-€40 ($38–$51) deals that included performances by various DJs, bull-running, dinner and return transport from the Spanish capital.
Videos of the first 'Mr. Happiness' party, held in April, showed smiling people having fun in the sun.
But bad weather caused organizers to stop Saturday's party earlier than planned. When attendees made their way to the car parks they found that only a few buses had been provided.
According to Spanish daily La Razon, some went back to the party venue to take shelter from the rain and wait for the return of the buses – which never happened.
Approximately 600 others decided to walk to the nearest town which resulted in the local Civil Guard having to close the road to traffic for several hours.
Officers provided assistance to a number of people who showed symptoms of hypothermia.
The event did not have any official permits and was technically illegal but the organizers blamed the bus company for what occurred.
"We agree it's right to refer to it as a scam, a scam suffered by all of us, both organizers and customers, a scam by the bus company, the company contracted that didn't fulfil its commitments," they wrote on their Facebook page.
"We hugely appreciate your understanding and support. And, of course, SORRY," they added.
Despite this, over 300 of those affected have contacted lawyers Juárez Bufete Internacional to jointly sue the organizers for damages and to demand the return of their money.
The "Mr. Happiness" clothing brand that sponsored the event was this week trying to distance itself from the rave's repercussions.
"For any doubts or complaints, we would appreciate it if you went to the page of the event," they posted on Facebook.