PHONE CALL request?

If you have a professional account (the £25+VAT per month subscription) then you can request a call when opening a new case, from the seller central homepage click the “help” (or “?”) button at the top-right, scroll down and click “get support”, then “selling on Amazon”, don’t bother typing anything into this box instead you scroll down and click “Or, browse for your issue in the menu”, find the most relevant subject for your issue, you should see a contact form open up, near the bottom of this form there should be 3 buttons “email”, “phone” and “chat”.
Phone or chat are not always available and aren’t available at all for certain contact categories… and again you need to be on the professional plan.

If you’re not on a professional plan, you can try requesting a call-back by replying to your existing case with a message along the lines of

Hello,
As this case has now gone on for [amount of time] without an amicable resolution, would you please be able to call me on [phone number] so that we might resolve this issue swiftly.
Regards,
[name]

Wouldn’t this get you through to the account health team?
Does this button even show up for people that don’t have the pro plan?

Fastest way would be here on the forum, open a new thread and explain the issue, someone should be able to help faster than Seller Support can.