returning item to seller

[ashot.khachatryan]

I've received a loco model which isn't as described.

Then I opened "return case" and sent back the model. The seller agreed refund money when he receive the model.

The parcel already in customs office since 28/09/2015. It's eighth day I'm waiting for my money. The seller suggest partial refund, because he have to drive about 50 km and pay customs fees.

How can I ask ebay for assistance? (there is not   "ask eBay to step in" under options) Or what other resolution exists for this problem?

thanks in advance.