How to explain to teacher that I can't do something?

My teacher wants us to sign up for this app thing, where we text a number, and it sends us reminders on things. Stuff like that never works on my phone, as I have an old LG slide phone. He sent out an email saying if you don't do it, you'll fail the class. But I can't do it! It literally destroys my phone. Also, I feel it's really unfair of him to assume all of us have phones and can do that.
Answers

Folie a deux

Talk to your teacher and explain your dilema. If he's not willing to help you out in some way, talk to your counselor. It's not fair to assume all students have this technology available.

bluebellbkk

If he doesn't KNOW that you don't have a phone capable of doing all that, then for heaven's sake TELL him. He's not a mind reader.

Gypsyfish

Also, if you're in high school, you can have your parents contact him and tell him that you don't have a phone with that capability and you're not going to have one. It's very wrong for him to assume that all students have a smart phone.

drip

Have a parent text him that you phone is old and doesn’t have that function.