There appears to be a bug (or perhaps a previously unforeseen scenario) with eBay’s relatively new shopping basket. If a buyer adds an item with carriage specified as “Freight” and another with collection in person to the shopping basket then it’s impossible to complete the purchase on eBay.
They buyer will see a message “Please go to Basket to request a total from the seller”, but that takes you back to the basket page but nowhere to request a total. You’re stuck in a never ending circle unable to buy.
The whole point of eBay’s shopping basket is that buyers can browse, but the goods aren’t theirs until they pay. Stopping buyers from paying is never a good thing, and whilst “Freight” or “Collection” is never an ideal shopping option, for some products where delivery has to be on a pallet delivery or worse a HiAb truck, freight is the only realistic option.
Currently what appears to be happening is that buyers are simply contacting the buyer and completing the purchase off eBay. That means there’s not buyer protection, no feedback for the seller, and no fees for eBay.
I’ve noticed similar issues myself, for instance when buying one product with 24 hour courier and another from the same seller with 2nd class post – eBay struggle to combine any items with dis-similar postage options.
Sadly we don’t have a solution for sellers, if buyers are struggling to purchase multiple items from you then you’ll probably never know unless they telephone or email you. For buyers the solution is simple, telephone or email the seller and they’ll doubtless be more than happy to arrange a way for you to pay, ideally on eBay but more than likely off eBay.