A nun has recounted how she has lost everything after fighting a legal battle over the sale of a historic L.A. convent, which pop singer Katy Perry wanted to buy for $14.5 million.

In an interview with the Daily Mail, Sister Rita Callanan said she had hundreds of thousands in the bank just a few years ago, but now her bank balance is zero and her healthcare check has already bounced on more than one occasion.

Callanan, who is one of the few living sisters belonging to the historic Order of the Immaculate Heart of the Blessed Virgin Mary in Los Angeles, is now suffering from cancer but she is not sure who is going to pay for her next round of treatment.

The 80-year-old nun's legal dispute with Perry began in 2015, when the singer struck a deal with the Royal Catholic Archbishop of Los Angeles (RCA), headed by Archbishop Jose Gomez, to purchase the convent for $14.5 million.

However, Callanan and her fellow Sister Catherine Rose Holzman opposed the sale, saying the convent has been the Order's property for 45 years and it is their right to sell it. The two nuns had quickly signed a deal to sell the convent for $15.5 million to restaurateur Dana Hollister before the archdiocese was able to finalize the sale of the property to Perry.

The archdiocese sued Hollister in an effort to void the deal and Los Angeles County Superior Court Judge Stephanie Bowick ruled that the nuns' attempt to sell the convent were improper.

In a tragic turn of events, Holzman suddenly collapsed and died in the Los Angeles courtroom last week, leaving only Callanan in the longrunning dispute with Perry and the RCA. She had vowed to keep on fighting and had set up a GoFundMe page to raise funds to help pay for legal costs.

"On March 9th, 2018 we tragically lost Sister Catherine Rose, my beloved fellow IHM Sister and original organizer of this GoFundMe campaign. She was my cherished partner in this ongoing legal battle to keep our convent. It is now more important than ever to continue this fight and for our cause to prevail," she said.

The property, located in the sits in the trendy Los Angeles suburb of Los Feliz, was purchased by Sir Daniel Donohue and his wife Countess Bernardine Murphy Donohue in the early 1950s. According to the Daily Mail, the couple had virtually given the property away to the nuns, who pooled their money together to buy it for £431,000 (US$600,753) in 1973.

Callanan said that if they were allowed to sell the property themselves, they would be able to use the money to provide for themselves in their old age.

"All we are asking is to sell our own property, keep our own money so we can take care of ourselves until the last person dies, then the money and property can go to the archbishop. There's not many more years, give me a break. He's supposed to be a chief shepherd," Callanan said.

Callanan said that she only learned about the deal with Perry through a realtor friend, and complained that the archbishop had not consulted the sisters when he sold the property.

She said that she will ultimately have to accept the court's decision, whichever way it turns out, although the other nuns in the U.S. are looking on at the unique case. She believes that that the dispute is a test case that could, if they lose, see any archdiocese stake a claim for ownership of convents within their area.