Ceylinco. Is verbal agreement legal btw employers and future employees and is it ethical what they did?

Ceylinco to my knowledge is a company of Sri Lankan origin. Although labour ministry and other regulations are very much in force in Malaysia, it ultimately depends on the "company culture" and management style of the each company. Upon finalising a job interview, yu should have asked for a written job offer from prospective employer. Chances are that if you approach MOL, company can always say that you were not selected in the first place.