My iPhone headphones have stopped working after 1 year

I guess you will have to get some new ones. Do any headphones work? If not, you may have a problem with the headphone jack. If needed get an appointment at an Apple Store for an evaluation.

Use the ones that work. If you want, get an appointment at an Apple Store so they can evaluate them and they will tell you your options. Since they are a year old, they probably won’t have any warranty coverage, so you may need to buy some new ones.