This is feedback extortion, totally against the rules, and you do not change the feedback for this reason.
You can if you like inform eBay of this message and they view these message seriously, link to Customer Services below.
Meanwhile , if you have received an item not as described and less than 30 days have passed from the item's last estimated date for delivery, listen to the seller no more, but just proceed this way:
Go right of the item in your Purchase History, and from More Actions select Return this item, selecting the reason... Item Does Not Match Description or Photos.
The seller has 3 days to accept the case, if they don't , you need to escalate on day 4, or within 30 days, and eBay will step in and force the refund.
If the seller wants the item back first, they need to pay for a fully tracked return postage. On receipt of their item they have 48 hours to refund you. Again, if they don't, you escalate the case.
One tip you may receive a postage label for 2kg this is standard if the seller does not adjust the weight of the item, if this happens just contact eBay Customer Services, they will provide the correct label for the weight, and charge it to the seller's account.
Under no circumstance close the case early for any excuse or promise the seller may give, and do not forget to escalate.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
I recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
@twain_harte_trains