the mandatory cell phone

Sophia University, as well as St. John's University, requires all exchange students to have a mobile phone. As for why, I can't quite understand. Frankly, buying a phone number, whether prepaid or contract, is just a waste of money because there are so many other means of communication, such as emailing and internet calling over some type of network. Since the majority of people have messaging applications that also allow you to call over wifi or 3G/4G, I feel that's all I really need.
Now, for solving this cell phone issue, I have no choice but to comply with the regulations.
In the handbook that Sophia gives you, it lists a couple of places where you can buy a cell phone. Around the campus, there is NTT Docomo and Softbank. What you will need is your student ID card, residence card, and credit card or bank passbook from Japan, not your home country. There will be a contract charge, as well as a monthly phone bill, which you can either arrange to have the funds automatically deducted or pay manually at any convenience store, bank, or post office.
Well, I actually have no idea how mobile phones work, US or Japan. Before I came to Japan, someone told me that I cannot use American phones in Japan because they run on a different system. Therefore, I did not bring my cell phone. In the US, I use a SIM card for my phone, but to do that here, the minimum contract is two years. Since I'm only here for four months, there is no point in signing a two-year contract, which is why most people opt for prepaid phones. Lucky for me, though, I have a friend who lent me an old cellphone that he no longer uses, so unfortunately, I can't tell you from personal experience how to deal with this cell phone issue. I can, however, help you out with getting a data plan. The phone my friend lent me is outdated and cannot do anything except make and receive calls, and send SMS messages. I plan on traveling a lot while I am here, so I feel much safer with a navigator. So yesterday, I went to Akihabara and bought a smartphone and a b-mobile SIM card. There are several different cards that you can choose from; I bought a b-mobile 3G/4G Fair SIM card. What this allows me to do is access a 3G network at 1GB per month for 120 days. My other friend from New York brought his own smartphone and actually went to the Docomo company and enrolled in an actual plan with them because he wanted unlimited data. Since he's also only here for one semester, he didn't sign the contract. The downside to no contract plans is that its much more expensive (he's paying about 6000 yen per month).
So, I feel this is quite a lot of information (especially for people like me, who have no idea about how phones operate), so I will make a few clarifications here:

1. For Sophia University students, a mobile phone with a working phone number is mandatory. The best thing to do for that is to buy a prepaid cell phone here (in Japan). As I mentioned before, my friend lent me his phone, so I don't really know much about it (regarding costs, etc), but I heard that you can buy the cheapest one (around 3000 yen), and if you need to make a voice call, have the other party call you instead because incoming calls are free. If you make an outgoing call, you, yourself will be paying for it.
2. For students who do not require voice and want data, bring your smartphone and then buy something called b-mobile. It's like a prepaid data card. I chose one that allows me to use up to 1GB per month for 120 days. In other words, once I use up 1GB, I won't be able to use any more data for the rest of the month. There are also other cards you can choose from (the amount of data, length of time, etc.).
3. If you want unlimited data, and are here for less than two years, it is much cheaper to pay a higher price per month with no contract than to sign a minimum two-year contract and have to pay monthly for two years, or the cancellation penalty.

I am quite disappointed at how unhelpful Sophia is regarding this cell phone issue. Seeing how extensive their exchange program is, you would think that there would be someone who could provide you with information on the options you have. Perhaps, it is partially my fault for not knowing enough about phone and data plans. After all, I have since become an adult and should do my own research.
Still, I can't help but feel a bit of hostility towards the school. As a student, I feel that we deserve and should be provided this guidance.