Do you have an invoice with all the items on it?
And then all the shipping charges combined to make a total that is too high?
Change the shipping total.
DON'T HIT RECALCULATE.
Send to your customer.
If you are the buyer, ask the seller to re-invoice you.
If he is really baffled, he can send you a Paypal Send Money invoice instead.
All the eBay transaction notes should be on it.
As a buyer you will still be covered by both eBay and PP's Buyer Protection policies.