Yellow Freight Deceit about pallet weight Nationwide

One pallet of rocks with 33 cardboard boxes (16"x12"x12") was shipped from a Tennessee university.  Each cardboard box weighted ~35-40lbs.  The samples were fragile and wrapped in bubble wrap and the boxes were not full.   The university department estimated the total weight at 1200lbs.  The loading dock at the university department did not have a pallet scale.  YRF said the weight was >2500lbs and charged me almost double the estimate.  I received the pallet and did not get the bill til later.  I am a 56 year old woman, not in the greatest of shape, and I can move these small cardboard boxes around without difficulty.  To meet the weight that YRF claims, each box would need to weigh 75lbs, which I could not manage.   YRF should have contacted my university before proceeding with the shipment when the weight estimate was more than twice.  My university did not weigh the incoming pallet so we have to 'trust' the weight from YRF.  I am convinced they added a steel plate or something to create a false weight.  I have used YRF for many years with shipping samples but this is the first time I have encountered such flagrant deceit from this company.  The customer service representative was absolutely rude.  When I did finally speak with a very polite manager, she assured me that she would check into the matter and call me back - but of course she never did and it's been several weeks.   I realize that it is my word against theirs so nothing will be done but I will not use YRF again.