Definitely 4 (set) - with 9 sets available

Quantity was revised on 25th March at 11.24

What I see

Click on 'see details' and what do you see?

My initial purchase was 17 March 2019 and paid straight away with paypal.

I clicked on your link again and got this -

So I see the confusion.

As far as I'm aware, people don't normally buy straight from there, they click on 'see details' for further info.

OK just tried that and it does open up to a listing with 4 items.  It also says, You bought the item and that the seller has updates this item you can view the Item I purchased.  This link also shows 4 items.  I hit the buy it now button on a page that stated 10 items though, different to the title on this listing.

Ok so others can see what I have used to purchase this item.  Now why does it do that and what to do about it.

When I purchased the item I did not look at the "see details" description as I way buying on Price per item from a search and being genuine Holden parts I went with it.

Ok so others can see what I have used to purchase this item.

No one else can see how you paid. Only you and the seller can.

Ebay is bad for this and I have seen this many times. I cannot fathom why they use that title to describe those 2 listings as it does not match the quantity as both only offer 4. 

I did find the original listing for 10 but it was around $100.