Why does our "granite" worktop mark so easily?
What some manufactures call quartz is actually ground granite and epoxy or Silestone. In most cases they are great and don't require sealing like solid granite does.  I suspect you may have purchased a bargain brand that is inferior to Silestone or solid granite or good grade Quartzite type. 
Also, do not confuse Stilestone or similar to real solid quartz which is a granite rich in pure clear or milky quartz.

If you feel you were mislead in your purchase, you could go raise a stink at the retailer. Insist they inspect your counters and make it clear you are not satisfied.