Bummer. Maybe hit the guns shows or try gunbroker.com and the other gun auction sites?
Maybe call Classic and ask them if they have any defective scopes and if so could you buy a rubber eye piece? Can't hurt to ask. At worst all they can say is no.
And that's the website I was thinking of but couldn't remember the name so didn't bother to try. lol
To save you time, I followed the link HK left for you and found the eye piece on page one. Is this it? The new style is on page 2.
http://www.kalinkaoptics.com/detail.aspx?ID=222