A letting agency in London has allegedly been charging prospective tenants hundreds of pounds to view properties.
According to an investigation for the BBC's Victoria Derbyshire programme, Flintons demanded cash payments up front before renters were allowed to take a look round potential homes.
Several clients of the letting agent claim they were told by Flintons that their payments would be refunded if they did not like the property.
However, they were reportedly told that the money would not be refunded after all following the viewings.
Israel Kujore, who responded to a Flintons advert with friend Harry, said that they paid £300 each to see one property before seeing bad reviews about the business online.
He told the BBC: '£300 is half my rent gone. What can I do? I don't have the money to sue them. I don't have legal expertise to deal with it – I'm powerless.'
Flintons told Victoria Derbyshire that they only took payments when someone wanted the property and that they had issued receipts telling customers that the money was non-refundable.
But Mr Kujore said he had not been given this document to sign until after they had made the payment and had merely been given verbal assurances that they would receive refunds.
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The Competition and Markets Authority says that to 'require a deposit from a tenant before they have been given the opportunity to inspect the property or the tenancy agreement' could constitute an 'aggressive practice' and be unlawful.
Shadow housing minister Melanie Onn called on the Government to give greater protection to renters, calling the Flintons allegations 'the tip of the iceberg'.
Flintons denied any wrongdoing, saying the payments were taken as a 'holding deposit' which were always non-refundable and it did not agree with customers' version of events.
- This article first appeared on Yahoo