GloryBells • 
Contact the seller and ask them to decline your offer. They are not required to.
Canceling a Best Offer
When you make a Best Offer or a counteroffer, you're agreeing to buy the item if the seller accepts. However, if you've made a mistake when making an offer or a counteroffer, you can retract or cancel it in certain circumstances.
You can retract a Best Offer or counteroffer if:
You accidentally entered the wrong offer amount (for example, you submitted an offer of $99.95 instead of $9.95)
The description of the item has changed significantly since you made your offer
You can’t get in touch with the seller
As well as the above, timing is also important. You can retract an offer if:
There are 12 hours or more left before the listing ends
The listing is ending in less than 12 hours and it's been less than an hour since you placed your most recent offer
You won’t be able to retract your offer if:
The seller has already accepted or declined your offer, or sent you a counteroffer
You’ve already made 5 offers in a specific category
If you’re using the eBay desktop site, here’s how to retract a Best Offer or a counteroffer if it meets the requirements above:
Go to Bids/Offers in My eBay.
Find the offer you’d like to retract.
Select Review offer, then select Retract offer.
You can also cancel your offer on the item page by selecting Review offer and then Retract offer. If you’re using a mobile browser or the eBay app, go to the Best Offer cancellation form to retract your offer.
Here is a link with more information:
https://www.ebay.com/help/buying/buy-now/making-best-offer?id=4019
When you make a Best Offer or a counteroffer, you're agreeing to buy the item if the seller accepts. However, if you've made a mistake when making an offer or a counteroffer, you can retract or cancel it in certain circumstances.
You can retract a Best Offer or counteroffer if:
You accidentally entered the wrong offer amount (for example, you submitted an offer of $99.95 instead of $9.95)
The description of the item has changed significantly since you made your offer
You can’t get in touch with the seller
As well as the above, timing is also important. You can retract an offer if:
There are 12 hours or more left before the listing ends
The listing is ending in less than 12 hours and it's been less than an hour since you placed your most recent offer
You won’t be able to retract your offer if:
The seller has already accepted or declined your offer, or sent you a counteroffer
You’ve already made 5 offers in a specific category
If you’re using the eBay desktop site, here’s how to retract a Best Offer or a counteroffer if it meets the requirements above:
Go to Bids/Offers in My eBay.
Find the offer you’d like to retract.
Select Review offer, then select Retract offer.
You can also cancel your offer on the item page by selecting Review offer and then Retract offer. If you’re using a mobile browser or the eBay app, go to the Best Offer cancellation form to retract your offer.
Here is a link with more information:
https://www.ebay.com/help/buying/buy-now/making-best-offer?id=4019
