I have purchased a set of cuttings from a dealer on E-bay. The price was good and I had purchased from this dealer before with good results. This time they send cuttings that were less than 1/8 inch in diameter I do not think that the cuttings will be good if they root. 
My question is what would you do?

If you had good experience with him before call him and let him know how you feel, and act accordingly.

I would contact the seller in a gentlemanly manner and express my concerns.

Geez, that is pretty small, pencil size is 1/4".
 
Dilemma for sure, I'd talk with the seller, usually people are reasonable, and being straight forward is the best way.  

But some people might think that is a normal cutting size. I did once send some similarly sized, but that was all I had and it was a gift.

I talk to the seller and share your concerns, I would be disappointed/ concerned if I was you too. Depending on the price you paid, you could return them??

Now here is the crux of the problem and the reason I have turned to the members the forum. I have talked to the seller (via msg) and he does not think that is a problem but he agreed to send  a different cutting to replace the small cuttings. So far he has not sent anything or corresponded. I sent another msg to reiterate my concern and asked for a for sure answer.  If they do not respond I think I will have to send a complaint to e_bay, but that would spoil his rating. The seller does not take back the item but they have offered to refund,etc. No response.

Get your cutting skills up. Thin cuttings with lots of nodes are easy to root. Now thin with a few nodes are harder but not impossible. Sometimes challenging yourself will make you better at your craft. Goodluck .

I would wait a week. Sometimes it takes a person a few days to ponder a better decision on a disagreement.

Can you show a pic of the cuttings? Seems like either they are fresh and green or old and dormant. What were they advertised as? 

I agree with Brian.  I used to think they wouldn't survive but 3 people sent me super thin cuttings.  One sent me 1 1/2 inch long tip cuttings that thin (as a favor to me, not as something I paid for) that he was going to throw away.  They all rooted.  I was stunned but I had several new plants of very good varieties.  And they didn't have to be babied any more than any other cuttings.  Now I'm grateful to all of my teachers who made me learn new things. 

Definitely try to get better cuttings but also try to root what you have.  Try a few different ways but start ASAP so the cuttings are as fresh as possible.

Hi,
Did you see a picture of the cuttings before buying ? Are they true to the picture ?
What was the text describing the item ?
If the item matches the description ...
Are the cuttings clean ? Or already dead ? Did you get just 1 ? Several ?
Of course, if you got just 1, then I would ask to get a better one, for sure.
If it looks healthy, I would try to root it and see what comes out.
I would tell the seller : ok, the cutting is thin, so my odds are not the best, but I'll try it. Should I fail, I'd like to get a better one .
See what he says.
The problem being, that the seller may have no other cutting for now, but will take more come fall ...

Agree with Brian. I take tiny cuttings off my RDB AND ROOT THEM. OR WHEN TAKING AND PROCESSING CUTTING THE LITTLE SMALL NODES THAT HAVE GROWTH ALSO ROOT THEM. BUT WHAT DID PAY FOR. WHAT DID THE DESCRIPTION SAY AND THE PIC. BY ANYWAY SELKER SHOULD JUST REFUND A UNHAPPY CUSTERMER. COST OF DOING BUSINESS

seller sent real cuttings. The replacement cuttings are much larger than the first cuttings. They paid shipping .

Hurrah! Smart to make a customer happy, so long it's no unreasonable. All any of us have to offer is service.