Ebay Needs Some Good It People Who Know How To Fix Issues !

Since March of 2021 I have not been able to send invoices for combined
shipping in eBay. I can send an invoice for one item only. If I try to combine and issue an invoice I get a message "something went wrong try later". Duh !! For over 10 months and dozens of phone calls and numerous emails The only answer I ever get is that they are working on it. This is not rocket science and you would think that by now someone in the IT dept.could fix this. All they do is create a new ticket when I call. I have tried various browsers and computers per their suggestion and nothing works. Anyone have have an in with eBay that could help resolve this issue. Its not only costly but time consuming to have to send my buyers a memo that when they pay I will adjust shipping with a refund . Everything worked fine for years until March 2021 !!
eBay needs to recruit some IT techs that really know how to fix things
Before I retired if my IT people couldn't fix an issue in a an reliable period of time I was shocked. They were good . Why can't eBay for as big as they are fix a simple problem ??

I have had more or less the same problem. When I tried to sent a combined invoice from the orders section in the sellers hub, I got the same message.
For me the solution was to sent an invoice from the orders awaiting payment section. When I did this, all the purchases were combined.
I now have made this my standard method of sending invoices.

Hans

eBay's IT scope is huge, few people appreciate what it is and how it gets done. eBay's infrastructure includes more than 25,000 Sun and IBM servers. They process over 250 checkouts per second 24/7/365 AND handle peaks even larger than that; on a daily basis eBay processes tens of billions of requests daily through their platform. They currently have over 70,000 software developers, a new version of their site is pushed out every two weeks. You cannot imagine what it takes in terms of revision control, management of the SDK tools and environments, and the sandbox test environments needed to test a small software change.

Also keep in mind that no company in the world can replicate all the custom computers and devices and their configurations. So sandbox testing is done with 'virgin' (fresh installs of all software) operating systems, operating system versions, and browsers. It is often impossible to even replicate the issue that users see in their computers, and if you cannot replicate the issue fixing it is nearly impossible (not saying this is the case here, I am not that familiar with this specific issue).
Don

As an aside, I was told by one major tech company that Google is all about availability so they have many servers running in parallel to ensure the data is available and quick. They design their own servers.

Google is exponentially larger than eBay, Google has north of 900,000 servers.
Don

Hans: I tried that from the awaiting payment for my orders and it still does not work. Thanks for trying though Mike

An eBay gentle SHOVE towards managed payments?

Of course you did this, but the below quote is from a Google Search, " eBay will not let me issue combined invoices" for which the first return was, "Sending invoices to buyers - eBay" which led to a page which had:

How to combine payments for a buyer

When a buyer purchases more than one item from you, you can combine their purchases into one invoice. It'll save you time, and you can offer the buyer a shipping discount.

To offer combined payments, you'll have to enable it on your account.
How do I enable combined payments?

Go to Manage shipping settings.
Select Edit next to Combined Payments.
Check the box beside Allow buyers to send one combined payment for all items purchased.
Select Save.