There is still an issue for sellers to combine postage, but buyers are unable to do this.
Best way forward is for the seller to cancel both orders with your acceptance , citing Buyer Requests to cancel, This fully refunds you, and their seller performance you can assure them is not affected.
Then, to relist both items as one listing for you to buy again.
Bit of a faff I know, but as said, it's something not yet ' fixed' under sellers' new Simple Delivery rules!
@camillahofc
