Can your job pressure you into buying a cell phone for business purposes?

The job is Fedex Freight. They don't provide a cell phone for their employees nor is it in the requirements for being hired. However, they keep pressuring me to get a cell phone because they feel you need to call your customers prior to delivery. I can't afford a hefty unlimited plan and that is what I would need. I used to have a cell phone but couldn't pay the bill because my job rang it up with all the calls. The job would call me nonstop, as well as other drivers, customers and everyone the job felt need to give out my number to and I would get yelled at if I didn't answer or respond to the calls. I had an unbelievable cell bill that I couldn't pay, I had to cancel with a $200 cancel fee with the cell company on top. Now the job wants me to get another one but they aren't going to pay for it.