Ebay Trouble - Value of a lens?

Bought a Min. 28105 RS in December through Ebay, which after lots of delays was finally delivered today.

The lens was described as "used but in good condition with no scratches on the lens,..."

Imagine my displeasure when finding a number of blemishes, a scratch and a damaged filter ring (see pics).

I paid about 110 USD (incl. shipping) for the lens and am now wondering, how much of a value reduction (50%?) is reasonable, considering that I expected a clear lens/filter ring when buying it.

Or should I just send it back for a refund (incl. delivery cost?) which might be a bit more of a hassle?

The lens was to be used as a cheap and light walkaround lens with the A99 and as an upgrade to my 28-85 I...

Any advice appreciated...

seriously reconsidering 2nd hand purchases, but unfortunately some lenses are just not available currently