A firm that claims to be one of the biggest travel insurance providers in the UK is facing two investigations into its conduct.
Travel Insurance Facilities (TIF) - which sells through the High Street chain Boots - is being accused of failing to provide proper care to policyholders.
According to an investigation in The Times newspaper, some patients were left stranded abroad.
However, TIF denies any misconduct.
A spokesperson for the company said the allegations were "extremely damaging, and not in the public interest".
TIF said it had taken steps to begin legal proceedings against the newspaper.
The General Medical Council (GMC) is investigating two doctors who work for the firm.
The Financial Conduct Authority (FCA) is also examining allegations against the company, after it was handed a 40,000 word dossier of complaints.
Those complaints contain claims that TIF habitually tried to delay or avoid making payouts.
'Left to die'
Nicholas Kingsbury, whose father died of sepsis in Ethiopia, claimed that TIF refused to evacuate him.
"My father bought Boots cover, but was left to die in a hospital that didn't even have a defibrillator," he told the Times. "Every McDonald's in Britain has one."
He said that TIF had decided that what his father needed was "peace and quiet".
The Times also reported a case of a 72 year-old man called Martin Blake, who paid £22,000 to fly home from Spain after suffering from a heart attack.
According to the Times, TIF had refused to evacuate him. He died in hospital in Wrexham a few days after his return.
Jacqui Skeel, from the Isle of Wight, told the BBC how she battled with TIF following a ski-ing accident in Bulgaria earlier this year.
After fracturing a pubic bone, she was taken to a local hospital which had no running hot water, and poor sanitation.
She said she phoned the company over 50 times to try and get transferred, but it was six days before she was taken to better facilities.
"They never responded to our calls," she said.
"I was left in there, in horrible conditions. At times I felt like I was in prison."
She has now filed a complaint with the Financial Ombudsman about the way she was treated.
In a statement released to the BBC, a spokesperson for TIF said, "When people fall ill abroad, naturally their first instinct is to want to come home. However this may not be best for them in medical terms to achieve the most optimal recovery.
Our focus is on the best clinical outcome based on expert advice, clinical fact, aviation medicine and our experience transporting unwell holidaymakers across the globe."
The company said it strongly refuted any suggestion that financial considerations influenced its decisions.
TIF was founded in 1996 in Kent, and trades under brands including Alpha Travel Insurance, Get Going, Holidaysafe and Ski Club Travel Insurance.
However, it is not a member of the Association of British Insurers (ABI).
"Travel insurers will act as quickly as possible to arrange and pay for the right treatment at the right medical facility and, if needed, arrange and pay for any emergency repatriation back to the UK," said a spokesperson for the ABI.
"Last year ABI members supported 159,000 travellers requiring medical treatment overseas, paying out £200m to cover medical bills."