I have tried to contact Ebay for help with an order that only half arrived. No luck

[nanadan7]

I ordered 4 drill bits. I got two only. I contacted the seller who answered in a couple of hours. He said sorry and how about he sends the missing drill bits to me now. I answered "NO" as I needed them now and without waiting another 10 + days to get them and I was going out to buy them elsewhere, and, that I wanted a refund immediately of the half the order that he failed to send.

That was over 30 hours ago and no refund and no further message. 

I have tried 5 times in Ebay, to try and start a case for my refund of that 50% of the order. It keeps putting me in sections that do not relate to my problem and I feel i cannot proceed. So saying, I've looked for a phone number/email ad to talk to Ebay but there appears to be nothing. How do I get my 50% refund from this errant seller?

Thanks for any clues here,

Nanadan