I bought an item which no longer exists, I want to change it to another item from the same seller.

[helenoftroy733]

I am new at this stuff and I included an old saved item in my purchase. I discovered that that item no longer exists and I would like to change it for a different item from the same seller with the same price and postage. How do I do that?  Sorry, I am elderly and not very wiyh it technologically...... helenoftroy733