Which is it, 'soyeuxdoux', - you want a combined shipping rate for 2 items to be paid on a single invoice? Or you want to cancel one of the items and only pay for one?
If you want to pay for two items on one invoice, try clicking Pay Now, as the combined rate is likely applied at checkout. If it is not, use the Request total link to the right of the items in your Purchase History and the seller will send an invoice for the combined amount.
This is the weekend, and the seller might have a family and a life and be doing something besides lingering around the computer waiting to send out invoices.
If, however, you want to cancel one of the purchases because you do not want to buy 2 after all, - then only the seller can cancel the sale. Again, you will have to wait, this time for a Cancellation to appear in your ebay messages. You then click to accept and click to agree, and then you no longer have to pay for the item.
In either case you need to contact the seller. Use the Ask a question link from one of the listings, or the Contact seller link to the right of the items on your Purchase History page. Only the seller can sort this out for you. No one here can wave a wand and clear it up. We're all just regular ebay people like yourself.
Good luck.
