hhgregg Will not accept brand new (2 weeks old) item in original, unopened packaging Greenville South Carolina

In South Carolina, I bought a king size mattress and two twin box springs from hhgregg (delivered 6/13/15).  I need to return the box springs because I've decided on a bed fram with slats.  The box springs are in original plastic wrap, unopened and I've had them for two weeks.

My wife was told by the centralized customer service in Indiana that we could exchange the box springs for a "bunkie bed" version (a miniature box spring designed for slat based bed frames) and he would speak with their buyer to see if they carried this item.  My wife did not hear back from them (Fred).  I spoke with customer service again and spoke with their manager (Jessica).  She states they cannot accept returns (box springs) and the olnly way to resolve my issue is for their vendor relations group to file a claim.  I stated that was ridiculous because my box springs are new, not defective, and filing a claim implies otherwise.  She stated I would hear back in two days.  Nothing.

Of course, I am not satisfied because these items are unused an unopened.  I do not understand why they cannot return these items and refund my $300.

My deliver receipt states that "all claims, returned goods, or service requests must be accompanied by this sales invoice.  All  returns must be within 14 days and have original packing material, all accessories and all insturction manuals".  I contacted them witin 14 days (although it should say 30 days according to Jessica).

hhgregg return policy is a follow from their websit (but not on their sales receipts - only a reference to go to their website):

"Serta iComfort comes with a 120-day trial period.  Trial periods and comfort guarantees apply only to mattresses and do not include foundations, adjustable bases or pillow, which cannot be returned.  For all other mattress purchases..

I am angry and, after spending $5500 for several items in my original purchase (and having bought other items from them before), I am being given the run around about a $300 new item return in unopened plastic.

They have lost me as a future customer and I will spread the news about how I was treated.