Triss thank you for the link! Few more bits of information from the 2009 link:
Iwona was planning her first ever summer holiday. Her female friend she has used to live with while studying suggested that they both go to London. She also stated that she will arrange job for Iwona with her good Polish friend at a shop for their little extra spendings. It was supposed to be two weeks holiday.
Iwona knew her family was very worried so she called them every day first three days. On third day she also send them postcard and arranged with her older sister that she will come to London in a week to visit her. They were both excited.
Iwona was very happy and excited in new city.
Fourth Day: Iwona went to work in Hammersmith, job her friend arranged. It was shop with crystal glass. She was helping older Polish man who came to London from Lodz. All what is only known about him that he was good friend of Iwona's friend from studies.
Around 4pm she had appointment with friends. She did not arrive and also did not come home where she stayed, at her female friend at Arndale Center in Wandsworth. Nobody ever heard from her again.
Polish police contacted Iwona's family about her disappearance. Family contacted Iwona's friend who she travelled with and lived in London. She stated she does not know anything.
London police searched the shop, owner's car and even digged up flooring of the shop. Nothing was found.
Family tried to hire private investigator in Poland, it was stated that they do not investigate abroad. They hired clairvoyant, who also gave up when family asked him to travel with them to London. They tried to hire private investigators in London, but it was way too expensive for them to afford. Missing flyers all over London, Itaka, Interpol and London police brought no leads.
Family theory: They think Iwona's disappearance was not coincidence. That all was arranged, from the beginning to the end and Iwona stood no chance.
Every year, on the day of 13th of July, when Iwona disappeared, family holds mass for her in local church.
http://www.dziennikwschodni.pl/magazyn/moja-corka-zaginela-dziewiec-lat-temu,n,1000089692.html