First, ask the seller to cancel your purchase because of the misunderstanding.
Ask in English and then use Google Translate to move your request into his language. Post both.
If he sends the request, agree immediately. Both of you will be released from the transaction and can leave feedback.
If he refuses, he can open an Unpaid Item Dispute, which takes over a week to resolve. If you do not pay, you get a Strike on your buying account. Two of those and you will find it difficult to bid on eBay since many sellers have an automatic Block on bidders with Strikes. On the other hand, you can request eBay to remove the first Strike because it is your first and everyone makes mistakes. Neither you nor the seller will be able to leave feedback.