So I purchased two Klir Filters (replacement for filter socks), from Aquacave, and on arrival both have previously been opened with parts missing.

The product is a piece of junk anyway.

Aquacave refuses to allow me to return. Many emails sent and when I called they said they couldn't find my orders

I have never had such a poor experience in my 50+ years of fishkeeping.

Contacted my credit card company for a refund

Avoid both IMO