Open Case in dispute center: what should I do?

[HZ88]

I recently ordered something online but only 1 of 3 items were sent to me.  Initially, not a single confirmation email was sent to me by the seller regarding what items were purchased and any comfirmation that that order was made at all.  Couple weeks later, I recieved one item and now the other two have yet to show up.  I opened a dispute on the order but paypal ends up sending me an email saying that the seller had provided shipping information.  While this is true, that was for the 1 item that was sent, and NOT the other 2 still to be receieved.  I wanted to contact paypal about this but I can't find any place on the resolution center where I can do this.  Any help would be appreciated.

[Whac-A-Mole]

if you make one payment for 3 items,and you receive just one item,then you should open a case of item not as described / missing quantity.

if you make 3 payments for 3 items,then open 2 cases of item not received.

It sounds like you open one case of item not received and seller upload tracking showing it has been shipped,so you lose.