A POST office manager is warning people to beware hoax callers after seeing a number of customers conned in recent weeks.

John Stokes, who manages Spar in Victoria Road, Dartmouth, has seen visitors to his post office conned out of as much as £5,000 by fraudsters posing as representatives of reputable companies.

One elderly woman arrived at the shop in tears, saying she was unable to pay her bills as a result of having money stolen and had received a letter from her energy provider threatening to turn off her gas and electricity.

Mr Stokes said: 'It's absolutely dreadful. I've had about three cases a week for the last month and it seems that good, trusting people are being exploited in the worst possible way. People come into the post office expecting to innocently transfer money, but I've stopped many of them who were conned into doing it. I just want to warn people before someone else has their life ruined.'

Evidence suggests hoaxers operate by accessing information from websites to gain customers' details – often the elderly and vulnerable – and telephone them in the guise of a company representative.

From there they encourage the victim to pay money through a voucher scheme, such as Ukash, a system which lets customers pay online by exchanging cash for a voucher.

As payments using vouchers are untraceable, the con artists can take the money and sever all further contact with the victims.

Bernard Cheek, who is in his 70s, was almost a victim of the scam until Mr Stokes convinced him he was being conned.

Mr Cheek, who lives in Dartmouth, said: 'I've taken part in the European Lottery Guild for several years but have stopped in the last nine months as I've been running a bit low on money.

'A man phoned me several times asking me to take part again and I insisted I wouldn't.

'A few weeks later he phoned me to say that my luck was in – as a loyal customer, they had put me in for a freebie and I had won 15,000 euros, about £10,500.

'The company then phoned again saying that although my win was free, I had to send £180 to a courier. I told them I couldn't because I had no money but then they told me that I could send two separate payments of £75 to make it better and cheaper for me.

'As I had been doing that lottery for several years, it seemed a reasonable request, so I drew £75 in the post office and it was then that John told me I was probably being conned.

'I phoned the police who have taken the information and are investigating. The case has reached the City of London Police fraud squad and I hope something gets done.

'I've since had calls from people saying they're from my phone company but I just put the phone down, I won't be fooled again.'

Mr Stokes said: 'It's awful how this made Bernard feel, I don't know how people can sleep at night.

'As a precaution, we no longer do Ukash vouchers and are being as vigilant as we can against the misuse of such schemes.

'I've had to comfort several distressed victims and I hope there won't be many more. Something needs to be done now.'

A Devon and Cornwall police spokesman said: 'It's very difficult to police something like this as there are scams all over the world, as well as up and down the country.

'The most we can do is take a complaint from someone and investigate it from there. The main rule for everyone is not to give any personal details over the phone. If the caller is persistent, blow a whistle down the receiver and they will soon leave you alone.

'Also be aware that most legitimate money matters are dealt with in writing, so if they don't have a postal address, don't get involved.

'You can also go on the telephone preference service to stop people from calling you.'

Those affected can also contact the national fraud and internet crime reporting centre, Action Fraud, which reassures people 'not to feel embarrassed if they have been conned or swindled' and advises that 'if an offer seems too good to be true, it probably is'. Visit actionfraud.org.uk or phone 0300 123 2040.