Using the layers approach, I first attacked the question by trying to locate a federal law, as to date I could not find any cases or laws that were applicable. I could not find any federal law requiring the employer to provide a cell phone or cell phone plan to an employee.
I then looked at the second layer on the model, state laws, there is only one state law, to date, regarding repayment of business expenses, and that state is California. Since I could not find any clues in the email of which state the company resided, I assumed that was not in the state of California.
I then went to local laws, this was largely unattainable, since it did not discuss the locality of the company.
As for the court cases, I only found the California case regarding reimbursement for business expenses. Again, I assumed the state was not California.
The next layer was then agreements, such as collective bargaining or employment contracts, although the email did not state a unionized work place. If there were such stipulations the email should have disclosed that information. As well as, in the email it would have stated that she was going to talk with her union representative.
Finally company policies, this was tricky. The employee manual had to state it had the right to amend their corporate policies with or without notice. That was to say if they had an original cell phone policy in the first place. If they did not have a policy, the company could require a cell phone and plan, as a bona fide job requirement. Does this make good business practices? No! As the human resources department our role is to remind management of the affect the new policy could have on moral. Which could also lead to a decrease in productivity and increase turnover. The new policy would decrease cost in the short-term, but potentially end up costing the company more than it was trying to save.
Overtime, since the email's only question was can the President "make us" purchase the phone and plan, I did not address the overtime laws. That is another legal problem to deal with, not the one we were asked.