Help feeling threatened

[jancruickshank-0]

I am having great difficulty with a seller. I am now feeling threatened by their messages. I have spoken to someone who says I have to wait 3 days before they will step in. Feeling very anxious as it's been a stressful time. What can I do please? 

[plpmr]

eBay to step in?

What case have you opened as you only purchased the item two hours ago and paid by PayPal [which is your right] when the listing asked for cash on collection.

You say in the neg you left that they wanted cash and would not accept PayPal and they won't give you your money back after you paid by PayPal.