Residents wanting to make home improvements on an Essex estate have been made to pay thousands of pounds in administration fees by the land owners.
One resident of the Burges Estate in Southend, Sara Foskett, was asked to pay £50,000 when she started work on an extension, BBC Inside Out discovered.
Consent is required by the freeholder, who can charge an administration fee.
Regis Group PLC said it had "acted responsibly" but has refunded some of the money and apologised to residents.
A spokesperson for the group said that the majority of residents had been asked to pay £250 plus VAT for the letter of consent.
Thousands of pounds has now been paid back to residents after BBC Inside Out's investigation.
More than 1,000 people live on the estate, which is made up of leasehold and freehold properties.
Mrs Foskett said she cried when she received the bill for £50,000, sent by Pier Management - part of Regis Group PLC.
"How could we ever be able to get that sort of money?" She said. "It would be selling the house."
Another resident, Kerry Staab, said she paid £17,000 for the letter of consent required before she could extend her house.
She is a freehold homeowner but still has the covenant in her deeds.
"We were horrified but our son was very unwell," Mrs Staab said. "We didn't have a choice."
Her son had been in hospital following a near-fatal industrial accident.
She said she had been waiting 16 months for her complaint to be resolved, but three days after the BBC approached Regis Group PLC she was given a refund of £15,500.
Mrs Staab said she was "over the moon" to have the money returned to her.
Mrs Foskett's fee was reduced to £900 and then cleared completely.
Ron Woodley, chairman of the Burges Estate Residents Association, said the landlords had been "taking the Mickey".
"There is no rhyme or reason why these amounts come in," he said. "It is arbitrary."
The group said it had already been successful in negotiating reduced fees of around £300 for more than 100 residents who went ahead with alterations without the consent letter they should have applied for.
Regis Group PLC said it was reviewing other cases, including ones in which residents had paid more than £1,000 for a letter of consent, even though their deeds specified a maximum fee of "two guineas".
"We wish to apologise unreservedly to any residents on the estate who are unhappy and who have suffered distress in cases where our policies and procedures have not been implemented to the standards we require," a spokesperson for the company said.
"We have over the last few months undertaken an extensive review of our practices."
The company announced it was selling its interest in the Burges Estate and negotiating with the residents' association to take over its management.
Essex Police said it was investigating to see if a crime had been committed.
Inside Out's film is on BBC One East on Monday at 19:30 GMT.