freight cost changing oddly

[accent3407]

A customer has changed his order total to 3 from 1, This is after I changed the offer to show I had 3 to sell.

He does buys now action and the freight goes from $5 to $10. These items are a few ounces each. 

How can I get the correct freight to apply?

Thanks

[ryry-jj]

What should the correct shipping be?  What is wrong with charging $10?

Also, BTW "freight" typically refers to heavy items carried on trucks as LTL or TL and moved around with pallet jacks or fork lifts.  For parcel post, "shipping" is a more common term when referring to shipping costs here on ebay

[ryry-jj]

Sorry, back to y our question....in your listing when selling multiples you can set a fixed amount for each additional unit purchase.  If one unit is $5, yo u can state each additional unit is $1, so 3 units would cost your buyer $7.  After the fact, all you acn do is refund what the buyer paid from what it cost you to actually ship, assuming the buyer is expecting a combined shipping discount in the first place