A lot of people are having trouble with eBay's CS phone service. I don't think anyone is hanging up on you on purpose, but there seems to be something wrong today.
Unfortunately you will not be able to do much until your item comes. Even then your choices are not great. If your seller is a dropshipper then they never had the item to begin with, just placed an order at a warehouse. It is almost impossible to get those cancelled.
In future always check and doublecheck, and add items to your Watch List until you are really sure. When the item arrives you can mail it back for a refund but you will have to pay return shipping because this is what is known as a "remorse" case, where the item doesn't fit. It is you who made the mistake. And you have to use TRACKED postage which can be expensive.
In a 'wrong item' situation where the claim is Not As Described the seller pays return shipping, either by purchasing a label for the buyer or sending the money. The buyer either uses/ purchases tracked postage, or it is given back to the seller.
If the item is on its way, not much you can do but wait to see it when it arrives. Maybe it will fit after all, or you can still get some use out of it somehow.
Oh, and always check a seller's feedback before you buy. 🙂
