Earpod warranty

Your EarPods should be covered under the Apple One (1) Year Limited Warranty (For Apple and Beats Branded Products Only) against manufacturing defects. As such, if you can show that this is that type of defect, you may be able to get a replacement pair for free. Otherwise, you can get a replacement set for around $29 USD. Apple will not repair them.

First, let's see if we can fix your problem. Follow these steps:

Try a full re-pair, reset, and try again.

Settings > Bluetooth > Airpods > Forget this device. Confirm it.

Put both Airpods in their case, charge them via Lightning for a few minutes (or preferably until the case is 100%). Unplug them. Open the case and hold the button on the back of the case for 15+ seconds or until the light flashes white. Hold them near your iPhone and see if the pairing screen comes up and pair them. If not, repeat until it does. But if you can't see the screen pop up, then manually pair within Bluetooth.

If it doesn't work, open a case with Apple Support here: https://support.apple.com/airpods

Or make a Genius Bar appointment (yes, you should bring your receipt although they should be able to see the warranty themselves) and if they can't fix them, they will replace them.

You just need to bring them with you and let the Apple Technician examine them. Manufacturing defects, although not rare, are not common either ... so be prepared to have to purchase the replacement set. It doesn't hurt trying.

Tesserax covered it.