EBay does not open Unpaid Item Disputes, only your seller can do this.
Since English is not your first language, there may have been some miscommunication.
Contact the seller and ask him what the problem was.
Also contact Customer Relations and appeal the Unpaid Item Strike, which could have serious effects on your abiltiy to buy on eBay.
If this is your only Strike, eBay can remove it.
You might go to Google Translate and enter your messages in your first language then have them changed to English. This may help with communication, although I don't actually find any problem with your communication skills. If you decide to do this post both the Englsh and other message together.