Assuming Maisy is an employee, who is Maisy’s employer, Technicalities or IS? (c) Assuming Maisy is an employee, has Maisy’s employer breached any contractual duty owed to her?

Question
In January 2014 Technicalities Ltd., a labour hire company, hired Maisy, an office worker. She was re-entering the workforce after being a full-time mother at home for two years. Technicalities placed her with a client, Innovative Storage. IS had Maisy work for them regularly throughout the year, and again in early 2015. Maisy also worked for other firms, but only on a casual basis. Technicalities reported that IS was satisfied with her work in May 2015, when they told her they would continue to need her until further notice, and she worked full-time for them until December 2015.
When she started work for Technicalities Maisy registered an Australian Business Number, as required by them. Technicalities said this was so they could pay her a flat hourly rate for all of the hours she worked and not offend any laws about penalty rates. She did not take work instructions from Technicalities though, but accepted directions from IS on a daily basis. She does not get paid when she takes sick leave or carers leave. Maisy always wore the IS uniform while at work and was receiving training in an accounts system on Friday afternoons in a spare office at IS until December 2015. Maisy made her own superannuation contributions and taxation payments. IS told Maisy when her hours of work were, what her duties were and with whom she would be working.
In late November Maisy had an accident at work. She slipped and fell down some stairs while carrying office equipment. A spill had occurred the day before, and although the cleaner had mopped up the oil, there was a residual coating on the stairs. Maisy injured her back, shoulder and left arm. She took a couple of weeks off work and asked IS to pay her medical expenses. They were reimbursed in full. Maisy continues to have a sore back and shoulder.
In early December 2015, Maisy saw a job advertisement online. It was for an office worker at IS. She applied in writing but did not succeed in her application. Maisy was not sure why she missed out and was not advised that the position advertised would make her continued services obsolete. The following week and after making inquiries of management she was informed by IS that she would receive two weeks pay in lieu of notice. Maisy has not received any further work allocations from Technicalities.

(a)Is Maisy an employee or another type of worker?
(b) Assuming Maisy is an employee, who is Maisy’s employer, Technicalities or IS?
(c) Assuming Maisy is an employee, has Maisy’s employer breached any contractual duty owed to her?