The school bus firm owner who had his contracts with two primary schools terminated just as the new year began, had also drawn complaints from other schools in the last three years.
The Straits Times understands that at least 10 more schools also had problems with the owner of bus firm Sindoz Group, known to some as Mr Andy Lee, with some cases going back to 2012.
This included the three pre-schools that contacted The Straits Times over the weekend to complain about Mr Lee after it reported about Red Swastika and Coral Primary ending their contracts.
One earlier case involved Creative O Preschoolers' Bay in Boon Lay, which in 2012 engaged Mr Lee's service under his firm, which was known as East Coast Transport Group at the time.
"He showed us company documents and gave us names of the other pre-schools he was working with, and he told us he ferried tourists too," said a spokesman of the school.
But his minivans were often late and, on a few occasions, he said his vans had broken down.
"One day, he stopped coming and stopped answering our phone calls," said the spokesman, adding that 27 parents had paid about $8,880 in all to Mr Lee. This has not been refunded although the parents have made a police report. One of the parents, Ms Rachel Chin, 40, who works in logistics, said: "Right from the start, the buses were late, sometimes by up to 30 minutes."
In August 2013, Chinese International School in Dunearn Road hired Mr Lee's bus firm as its school bus operator, charging $720 to $1,575 per student for each semester, according to documents obtained by The Straits Times. Parents said Mr Lee collected one month's bus fare on top of a $200 deposit from each child, but provided less than one month of transportation.
Former staff members of Mr Lee's firm, who spoke on condition of anonymity, said he sometimes operates under a different company and uses a different first name - he was previously known as Ady. They said he insisted on advance bus fees of up to two months and would go to the workplaces of parents to collect the fees. But after the money was collected, he would not respond to calls or replied to messages only hours later.
When parents and schools found his services unsatisfactory and tried to end their contracts, he would threaten to sue them.
At Red Swastika and Coral Primary, the parents of more than 200 pupils had paid at least $50,000 in all to Sindoz.
At Red Swastika, Sindoz could not confirm transport arrangements with parents; at Coral Primary, buses were late by up to one hour on the first school day.
The Ministry of Education (MOE) said on Tuesday that it is working with the two schools to ask Sindoz to refund the parents.
"MOE does not rule out further action against Sindoz Group," a spokesman added.
Yesterday, lawyer Doris Chia from David Lim and Partners said it would be hard to get a refund even if parents were to sue the firm. "Even if one is successful, the ability to recover the debt depends on whether the company has the money to pay," she said.
Contacted yesterday, Mr Lee repeated "no comments" when asked about fresh allegations and if he would refund the affected parents.