Daniel Burton ran seminars to show other property speculators how to rent and then sublet to as many people as possible. Now he has disappeared – and so have many tenants' deposits

A self-styled property expert who boasted of making £35,000 a month from a get-rich-quick scheme called rent-to-rent has gone missing, leaving tenants across London hundreds of pounds out of pocket.

Guardian Money first reported on Daniel Burton, 25, in June as part of an investigation into a new craze in the property market called rent-to-rent, also known as rent-the-rented and multi-let. The idea was to rent a property from an existing landlord, then turn a profit by increasing the rent further by sub-letting every possible space and cramming in the maximum number of tenants – all without having to put down any capital.

Burton claimed to have let out 200 rooms in 40 properties and ran paid-for seminars to show other property speculators how to repeat his trick – which also involved stripping tenants of their usual rights against eviction.

But only four months later, the London School of Economics dropout has disappeared, leaving a trail of tenants fearing that their deposits, some for more than £700, will never be returned.

The website for Burton's company, Unida Place, has gone offline, the phone line to the business has been cut off, and emails are ignored. The same goes for Burton's other business, letting agency Alexander George Estates, which has the same registered address.

The Guardian paid a visit to Unida Place's two offices in Charlotte Street in Soho. There we found a sign in the window stating "Alexander George no longer operates from this building" and directing inquiries to a neighbouring business.

Those neighbours told us Burton had moved out "in secret" some time in August. Since then numerous landlords and tenants have come knocking at the premises, looking for him and money owed to them.

Charlie Jones rented via Unida Place while he was studying at the London College of Fashion. The 21-year-old was one of five sharers in a Southwark house with a kitchen but no living room. "I am a victim and feel very distressed about it," he says. "I am still awaiting my deposit of £710 and have been for two months."

By law, tenants' deposits must be protected in an approved tenancy deposit scheme, but some of Burton's tenants commonly claim their deposits weren't protected, nor returned when they moved out.

Other ex-tenants spoke to Guardian Money on condition of anonymity. One 26-year-old from France came to London to do an internship related to his master's degree. "In my case, I left my flat at the end of August and am still waiting to get my £500 deposit back. They disappeared and don't reply to any phone calls or emails," he says.

Another victim, Sue (not her real name), explained how she paid Unida Place a year's rent upfront in September 2012, in return for a discount. New flatmates who arrived on 1 August this year were under the impression they could stay for several months – but Unida Place wrote to the household just days later telling them all to move out by 31 August.

Sue, 20, is yet to receive her deposit back. "I really am at a loss over what to do. I called Unida Place's office many times before and after I moved out, without ever getting an answer; they also never responded to any emails," she says, "Eventually I went to their office, only to find it was completely empty."

Concerns about Daniel Burton and Unida Place go back some time. Spanish web designer Xavi Esteve set up a blog, xaviesteve.com, in September 2011, partly to detail his poor experience with Unida Place. The blog has become a sounding board for the agency's victims. Numerous tenants tell tales of unreturned deposits – but landlords have also been victims too.

On 9 September 2013 "Mark" posted: "I'm a landlord and he still owes me a full month's rent. On top of this, the flat was rented to him personally and he illegally sublet it as Unida Place to seven people."

Another user, "AL", wrote that he moved out in May but hadn't received his deposit back. He went to Unida Place's Charlotte Street office but found they had moved out. Going through the mail he found several unopened court orders. "The next thing I did was to find the landlord of the flat I rented and it turns our Unida Place owe them rent as well," he posted.

So what has happened to all the rent that has not been passed to landlords, and to tenants' deposit money? That remains unclear as, despite many attempts by Guardian Money to contact Burton by both phone and email, he has not responded.

Vanessa Warwick, co-founder of landlord community Property Tribes, has long been sceptical about rent-to-rent schemes, and concerned about Burton's get-rich-quick claims at seminars and networking events.

She says: "When Burton first appeared on the scene, speaking at events, and making outrageous claims about the money he was earning, I was immediately concerned. My first thoughts were for his tenants and landlords. Were they being serviced properly by a relative newcomer to the scene with unproven methods?

"Then I became concerned for other people lapping up his get-rich-quick claims at seminars and networking events, as this would again impact negatively on tenants and landlords if Burton was not teaching the correct protocols.

"This case once again highlights how landlords and tenants should let through accredited agents with professional standards and client money protection in place to minimise their risk of losing money."

For those desperate to hear more about his successful career – or track him down for other reasons – Burton was due to speak at a Property Investor Academy event in Maidenhead on 26 October. Delegates paying £249 a head could "follow Daniel's proven blueprint for cashflow". But the academy told Guardian Money it is suspending all events featuring Burton.