The 2012 event was halted near the end of its first day amid reports that the site was overcrowded. Bloc was placed into administration a week later.
In a post on the Bloc Facebook page, organisers first explained they were told to "hang back from all public conversations about the festival" while administrators worked.
"At 23:45 on Friday 6th July, we took the decision to cancel the festival midway through its first night, owing to concerns for crowd safety," the statement read.
"We are very grateful to the Metropolitan Police for their support in assisting with the evacuation but we would also like to make it clear that, contrary to some reports, it was our decision to cancel the event."
It added that the license held by London Pleasure Gardens Ltd was for a capacity of 12,000 to 25,000 people and that 15,786 tickets were sold by Friday, July 7.
"We took tickets off sale two days in advance and it is accepted by all concerned that we did not oversell the event," organisers added.
Problems with "management of the admission control systems" were admitted and overcrowding in queueing areas led to the suspension of comprehensive ticket scanning at 9.27pm.
"Knowledge of the suspension of scanning combined with ticket touting enabled people to gain entry to the event without having purchased a ticket from our website," Bloc said.
Organisers also blamed delays with the building of the London Pleasure Gardens site, with missing venues and infrastructure leading to a concentration of revellers in corner of an otherwise large site.
"When the extent of the missing infrastructure was revealed, we considered our options," they said.
"London Pleasure Gardens was clearly a long way from the 'riverside arts and entertainment destination' that we had hired but our relatively small company lacked the resources to cover the costs associated with a postponement or cancellation of the festival or a legal action against the venue."
Bloc continued: "The venue had originally seemed like the perfect new home for Bloc so we're really sorry that everyone was let down.
"All of you who bought tickets, travelled from afar and have supported us through many years of festivals, and parties and clubs before that, deserved better.
"Following five successful editions of the Bloc festival, this year we could not deliver what we had planned - we cannot stress enough how sorry we are for this.
"We've learned from these experiences and have humbly taken on board the criticisms levelled at us."
Those seeking refunds are advised to print off a form via administrators Parker Andrews.