Sorry about the trip. Here are your options.
Not travelling at all
Your eSIM was delivered when you paid, so it can't be refunded (refund rules). If it hasn't been installed yet, don't install it: it can still be used for a later trip to the same place within 180 days.
Trip postponed
You can keep the eSIM. Install it any time up to 180 days after you bought it, and the plan only starts when it first connects at your destination. When plans start.
Already installed
An installed eSIM can't be refunded either (see the terms).
But if it has never connected at your destination, the plan hasn't started. Leave it on your phone (don't delete it) and use it on a later trip to the same place: the days only start when it first connects there.
Talk to us anyway if something's unusual and we'll look at it.