If you want eBay to reply, OP, then ask eBay.
You are posting on a community members board, not on an eBay request board.
You've said several times that buyers can cancel your purchase, but it’s apparent you mean sellers. This is an easy-to-mistype error; we’ve all done it. However, sellers have no obligation to cancel a sale upon a buyer’s request. They would be doing it solely to avoid a problem transaction, not because it’s mandatory.
These boards are full of threads about both buyers and sellers being unhappy with Sendle. In fairness, the couriers used by Sendle do also have their fans; it’s clear that those various couriers provide better service in some areas than in others. But there are also horror stories…
If you want your items to be sent by Australia Post, fair enough. I’d suggest you message sellers before buying, asking them to confirm they’ll be sending via AP, not Sendle, as couriers used by Sendle have caused problems with delivery for you in the past.
Really no need to be snarky on these boards. People who post here have a wealth of experience and will be happy to give information and advice if you need it - but it is rare (not unknown, but rare) for eBay employees to contact any eBay member posting here. Certainly no eBay employee has actually posted on the boards for years.
I’m not sure how you plan to “mute” anyone…
As to eBay being interested in or taking action on your request re Sendle, it’s Buckley’s to a hellish snowball’s chance; eBay not only provide Sendle as an option for sellers but they also actively push Sendle as the most in-your-face postage option so that inexperienced or confused sellers may not even realise at the time of listing that they have specified Sendle.
As I said, contacting sellers pre-purchase is probably the best way to go.
