Please don't encourage buyers to raise claims before contacting the seller. This will only create headache for both sellers and buyers as claims will take longer to resolve.
Contact the seller and explain your issue properly. If he doesn't reply within 2 days you can raise a claim on ebay.
Please note that ebay allows refunds in only the following cases;
- Didn't receive the product
- Product is not as shown on ebay
- Product is not working and has no warranty
If you didn't like the product or had a change of mind, it's upto seller to decide whether to accept your case or not.
