Josie Capone wanted to bury her son Joey, who was killed at the age of 17 after being hit by a bus, in the same graveyard as her parents.
But when she contacted Services Corporation International, American owners of Streatham Park Cemetery in south London, she says she spoke to a man described as a "memorial counsellor" who urged her to buy not only a plot for her son but also adjacent space for the rest of her family.
Likening him to a timeshare tout in Tenerife, she said: "All he seemed interested in was what I was planning to do about the rest of my family's graves. He said the plots were selling like hot cakes and I would have to buy now to make sure we could all be together. He persuaded me to buy four double graves for a total of pounds 5,200 and wouldn't take no for an answer. The next day my sister Jan went and put down pounds 500 as a deposit."
SCI, based in Houston, Texas, moved into Britain three years ago and is now the country's second biggest funeral director. It owns three cemeteries, 14 crematoria and 550 funeral homes, and is involved in one in eight funerals. Its sales techniques have been criticised previously by clergymen, undertakers and politicians.
Mrs Capone's daughter, Josephine, 23, said: "When you are grieving you are just so vulnerable you will say anything to get these people out of your face."
A local undertaker helped the Capones to recover the deposit and ensure that no contract to purchase eight graves at Streatham Park cemetery, south London, was ever signed.
A spokesman for Services Corporation International denied its staff employed high-pressure sales techniques.