The earphones that came with this phone were faulty

Dear sir/madame

I received my new Iphone 11 in October. The earphones that came with this phone were faulty. I did not start using the earphones until a few months later (I was using my old earphones). When I started using them, I noticed that the connection of the earphones were bad when I started using them. My music would cut out and pause all the time, or sound would start playing out loud even though they were plugged in. More recently, SIRI started to activate randomly when they were plugged in. Now, one of the earphones has stopped working completely. I had planned to go into the store but because of the corona virus I have been unable to do so.

Please advise how I can rectify this problem

Thank you.

[Re-Titled by Moderator]