Miss Ayelabola has since returned to her home city of Lagos, where she is a successful make-up artist.
She said: "I have never received my bill. If I had it, I would pay it."
It follows claims by NHS whistleblowers that managers are instructing them to turn a blind eye to health tourists because it is 'too much trouble' to chase them for money.
According to NHS estimates, only around 16 per cent of the cost of treating foreigners who travel to Britain to receive treatment is ever recouped.
Miss Ayelabola obtained a visitor's visa soon after discovering she was pregnant in 2010, travelling to the UK to stay with her younger sister, Stella, early in her pregnancy.
She gave birth to two boys and three identical girls at Homerton Hospital in Hackney, in April 2011 - seven weeks premature. She had a complex caesarean and remained in hospital for almost two weeks after the birth at a cost of £145,000 to UK taxpayers.
Although her visa expired, Miss Ayelabola continued living in her sister's flat in Poplar, east London, after the births and did not return home until February 2013.
Miss Ayelabola's children are now four years old and attending a private school.
She told the Mail: "What is it that's my fault? I don't understand.
"They blamed me that I came to the UK and I just came to use the system, which I did not do.
"If it (health tourism) is a problem in the UK, you should talk to the NHS. I have never received my bill. If I had it, I would pay it."
She said that she was allowed to stay in the UK without needing to ask and without having to apply.
"I did not want to stay... it was just my situation," Miss Ayelabola added.
It is understood Miss Ayelabola is separated from her wealthy husband, Ohi Nasir Ilavbare, but he is still involved in the children's lives and is believed to pay for their education.
Miss Ayelabola is understood to have left the UK voluntarily in February 2013, following contact with the Home Office. It is believed she has been banned from returning to Britain for five years.
In the UK hospitals try to claw back the cost of treating foreign patients after they are discharged.
In France, Germany and Scandinavia, patients must pay in advance.
Official estimates of the cost to the NHS range up to £2billion but some commentators say the true figure is likely to be far higher because there is no proper recording system in place.
Homerton Hospital said it would not be contacting Miss Ayelabola for the payment, despite her assertion that she would pay up if she received a bill.
A spokesman said: "If she wishes to contact us, we would urge her to do so.... But we will not be contacting her."
He added that Miss Ayelabola received a bill more than six months after she was discharged in 2011, which was returned to the hospital unopened. No further attempts were made to bill her, it is understood.
A spokesman for Homerton University Hospital NHS Foundation Trust added: "We hope the five children have prospered and are healthy. We would be pleased to reopen dialogue with Miss Ayelabola about her outstanding bill."
A Department of Health spokesman said: "It is completely unacceptable that people living outside the UK think they can abuse our NHS. We expect and are supporting the NHS to make every effort to reclaim money owed to it."
